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In this case, the length of thebuilt-in UDF evaluates each row of the stringthestring_col values. 

As we see how a built-in UDF works let's see what kind of built-in UDFs the Apache Hive has.

...

Return Type

Name(Signature)

Description

OSS

bigint

count(*), count(expr), count(DISTINCT expr[, expr...])

count(*) - Returns the total number of retrieved rows, including rows containing NULL values.

count(expr) - Returns the number of rows for which the supplied expression is non-NULL.

count(DISTINCT expr[, expr]) - Returns the number of rows for which the supplied expression(s) are unique and non-NULL. Execution of this can be optimized with hive.optimize.distinct.rewrite.

GenericUDAFCount

double

sum(col), sum(DISTINCT col)

Returns the sum of the elements in the group or the sum of the distinct values of the column in the group.

GenericUDAFSum

double

avg(col), avg(DISTINCT col)

Returns the average of the elements in the group or the average of the distinct values of the column in the group.

GenericUDAFAverage

double

min(col)

Returns the minimum of the column in the group.

GenericUDAFMin

double

max(col)

Returns the maximum value of the column in the group.

GenericUDAFMax

double

variance(col), var_pop(col)

Returns the variance of a numeric column in the group.

GenericUDAFVariance

double

var_samp(col)

Returns the unbiased sample variance of a numeric column in the group.

GenericUDAFVarianceSample

double

stddev_pop(col)

Returns the standard deviation of a numeric column in the group.

GenericUDAFStd

double

stddev_samp(col)

Returns the unbiased sample standard deviation of a numeric column in the group.

GenericUDAFStdSample

double

covar_pop(col1, col2)

Returns the population covariance of a pair of numeric columns in the group.

GenericUDAFCovariance

double

covar_samp(col1, col2)

Returns the sample covariance of a pair of numeric columns in the group.

GenericUDAFCovarianceSample

double

corr(col1, col2)

Returns the Pearson coefficient of correlation of a pair of numeric columns in the group.

GenericUDAFCorrelation

double

percentile(BIGINT bigint col, p)

Returns the exact pth percentile of a column in the group (does not work with floating point types). p must be between 0 and 1. NOTE: A true percentile can only be computed for integer values. Use PERCENTILE_APPROX if your input is non-integral.

UDAFPercentile

array<double>

percentile(BIGINT bigint col, array(p1 [, p2]...))

Returns the exact percentiles p1, p2, ... of a column in the group (does not work with floating point types). pi must be between 0 and 1. NOTE: A true percentile can only be computed for integer values. Use PERCENTILE_APPROX if your input is non-integral.


double

percentile_approx(DOUBLE double col, p [, B])

Returns an approximate pth percentile of a numeric column (including floating point types) in the group. The B parameter controls approximation accuracy at the cost of memory. Higher values yield better approximations, and the default is 10,000. When the number of distinct values in col is smaller than B, this gives an exact percentile value.

GenericUDAFPercentileApprox

array<double>

percentile_approx(DOUBLE double col, array(p1 [, p2]...) [, B])

Same as above, but accepts and returns an array of percentile values instead of a single one.


double

regr_avgx(independent, dependent)

Equivalent to avg(dependent). 


double

regr_avgy(independent, dependent)

Equivalent to avg(independent). 


double

regr_count(independent, dependent)

Returns the number of non-null pairs used to fit the linear regression line. 


double

regr_intercept(independent, dependent)

Returns the y-intercept of the linear regression line, i.e. the value of b in the equation dependent = a * independent + b.


double

regr_r2(independent, dependent)

Returns the coefficient of determination for the regression. 


double

regr_slope(independent, dependent)

Returns the slope of the linear regression line, i.e. the value of an in the equation dependent = a * independent + b. 


double

regr_sxx(independent, dependent)

Equivalent to regr_count(independent, dependent) * var_pop(dependent). 


double

regr_sxy(independent, dependent)

Equivalent to regr_count(independent, dependent) * covar_pop(independent, dependent). 


doubleregr_syy(independent, dependent)

Equivalent to regr_count(independent, dependent) * var_pop(independent).


array<struct {'x','y'}>

histogram_numeric(col, b)

Computes a histogram of a numeric column in the group using b non-uniformly spaced bins. The output is an array of size b of double-valued (x,y) coordinates that represent the bin centers and heights

GenericUDAFHistogramNumeric

array

collect_set(col)

Returns a set of objects with duplicate elements eliminated.

GenericUDAFCollectSet

array

collect_list(col)

Returns a list of objects with duplicates. 

GenericUDAFCollectList

intntile(INTEGER x)

Divides an ordered partition into partitioninto x groups called buckets and assign a bucket number to each row in the partition. This allows easy calculation of tertiles, quartiles, deciles, percentiles, and other common summary statistics.

GenericUDAFNTile

...

Normal user-defined functions, such as concat(), take in a single input row and output a single output row. In contrast, table-generating functions transform a single input row into rowinto multiple output rows. UDTF are one of the most advanced functions.

Row-set columns types

Name(Signature)

Description

OSS

T

explode(ARRAY<T> a)

Explodes an array to multiple rows. Returns a row-set with a single column (col), one row for each element from the array.

GenericUDTFExplode


Tkey,Tvalue

explode(MAP<Tkey,Tvalue> m)

Explodes a map to multiple rows. Returns a row-set with a two columns (key,value) , one row for each key-value pair from the input map.

int,Tposexplode(ARRAY<T> a)Explodes an array to multiple rows with an additional positional column of int ofint type (position of items in the original array, starting with 0). Returns a row-set with two columns (pos,val), one row for each element from the array.GenericUDTFPosExplode

T1,...,Tn

inline(ARRAY<STRUCT<f1:T1,...,fn:Tn>> a)

Explodes an array of structs to multiple rows. Returns a row-set with N columns (N = number of top level elements in the struct), one row per struct from the array.

GenericUDTFInline

T1,...,Tn/rstack(int r,T1 V1,...,Tn/r Vn)Breaks up n values V1,...,Vninto r rows. Each row will have n/r columns. r must be constant.GenericUDTFStack
string1,...,stringnjson_tuple(string jsonStr,string k1,...,string kn)Takes JSON string JSONstring and a set of n keys, and returns a tuple of n values. This is a more efficient version of the get_json_object UDF because it can get multiple keys with just one call.GenericUDTFJSONTuple

string 1,...,stringn

parse_url_tuple(string urlStr,string p1,...,string pn)

Takes URL string URLstring and a set of n URL parts, and returns a tuple of n values. This is similar to the parse_url() UDF but can extract multiple parts at once out of a URL. Valid part names are: HOST, PATH, QUERY, REF, PROTOCOL, AUTHORITY, FILE, USERINFO, QUERY:<KEY>.

GenericUDTFParseUrlTuple

String Functions

There is no good engine without string withoutstring manipulation functions. Apache Hive has rich built-in string instring functions. 

Return Type

Name(Signature)

Description

OSS

int

ascii(string str)

Returns the numeric value of the first character of str.

UDFAscii

string

base64(binary bin)

Converts the argument from binary to a base64 stringbase64string.

UDFBase64

intcharacter_length(string str)Returns the number of UTF-8 characters contained in str. The function char_length is shorthand for this function.GenericUDFCharacterLength
stringchr(bigint|double A)Returns the ASCII character having the binary equivalent to A. If A is larger than 256 the result is equivalent to chr(A % 256). Example: select chr(88); returns "X".UDFChr

string

concat(string|binary A,string|binary B...)

Returns the string or bytes resulting from concatenating the strings or bytes passed in as parameters in order. For example, concat('foo', 'bar') results in 'foobar'. Note that this function can take any number of input strings.

GenericUDFConcat

array<struct<string,double>>

context_ngrams(array<array<string>>, array<string>,int K,int pf)

Returns the top-k contextual N-grams from a set of tokenized sentences, given a string astring of "context". See StatisticsAndDataMining for more information.

GenericUDAFContextNGrams

string

concat_ws(string SEP,string A,string B...)

Like concat() above, but with custom separator SEP.


GenericUDFConcatWS

string

concat_ws(string SEP, array<string>)

Like concat_ws() above, but taking an array of stringsofstrings.

string

decode(binary bin,string charset)

Decodes the first argument into a String string using the provided character set (one of 'US-ASCII', 'ISO-8859-1', 'UTF-8', 'UTF-16BE', 'UTF-16LE', 'UTF-16'). If either argument is null, the result will also be null.

GenericUDFDecode

stringelt(N intNint,str1 stringstr1string,str2 stringstr2string,str3 stringstr3string,...)

Return string at index number. For example elt(2,'hello','world') returns 'world'. Returns NULL if N is less than 1 or greater than the number of arguments.

GenericUDFElt

binary

encode(string src,string charset)

Encodes the first argument into a BINARY using the provided character set (one of 'US-ASCII', 'ISO-8859-1', 'UTF-8', 'UTF-16BE', 'UTF-16LE', 'UTF-16'). If either argument is null, the result will also be null. 

GenericUDFEncode

intfield(val T,val1 T,val2 T,val3 T,...)

Returns the index of val in the val1,val2,val3,... list or 0 if not found. For example field('world','say','hello','world') returns 3.
All primitive types are supported, arguments are compared using str.equals(x). If val is NULL, the return value is 0.

GenericUDFField

int

find_in_set(string str,string strList)

Returns the first occurance occurrence of str in strList where strList is a comma-delimited string. Returns null if either argument is null. Returns 0 if the first argument contains any commas. For example, find_in_set('ab', 'abc,b,ab,c,def') returns 3.

UDFFindInSet

string

format_number(number x,int d)

Formats the number X to a format like '#,###,###.##', rounded to D decimal places, and returns the result as a string. If D is 0, the result has no decimal point or fractional part.

GenericUDFFormatNumber

string

get_json_object(string json_string,string path)

Extracts json JSON object from a json JSON string based on json JSON path specified, and returns json JSON string of the extracted json JSON object. It will return null if the input json JSON string is invalid.

Note
titleNote

The json path can only have the characters [0-9a-z_], i.e., no upper-case or special characters. Also, the keys *cannot start with numbers.* This is due to restrictions on Hive column names.


UDFJson

boolean

in_file(string str,string filename)

Returns true if the string str appears as an entire line in filename.

GenericUDFInFile

int

instr(string str,string substr)

Returns the position of the first occurrence of substr in str. Returns null if either of the arguments are null and returns 0 if substr could not be found in str. Be aware that this is not zero-based. The first character in str has index 1.

GenericUDFInstr

int

length(string A)

Returns the length of the string.

GenericUDFLength

int

locate(string substr,string str[,int pos])

Returns the position of the first occurrence of substr in str after position pos.

GenericUDFLocate

string

lower(string A) lcase(string A)

Returns the string resulting from converting all characters of B to lower caselowercase. For example, lower('fOoBaR') results in 'foobar'.

GenericUDFLower

string

lpad(string str,int len,string pad)

Returns str, left-padded with pad to a length of len. If str is longer than len, the return value is shortened to len characters. In the case of an empty pad stringpadstring, the return value is null.

GenericUDFLpad

string

ltrim(string A)

Returns the string resulting from trimming spaces from the beginning(left-hand side) of A. For example, ltrim(' foobar ') results in 'foobar '.

GenericUDFLTrim

array<struct<string,double>>

ngrams(array<array<string>>,int N,int K,int pf)

Returns the top-k N-grams from a set of tokenized sentences, such as those returned by the sentences() UDAF. See StatisticsAndDataMining for more information.

GenericUDAFnGrams

intoctet_length(string str)Returns the number of octets required to hold the string str in UTF-8 encoding.  Note that octet_length(str) can be larger than character_length(str).GenericUDFOctetLength

string

parse_url(string urlString,string partToExtract [,string keyToExtract])

Returns the specified part from the URL. Valid values for partToExtract include HOST, PATH, QUERY, REF, PROTOCOL, AUTHORITY, FILE, and USERINFO. For example, parse_url('http://facebook.com/path1/p.php?k1=v1&k2=v2#Ref1', 'HOST') returns 'facebook.com'. Also, a value of a particular key in QUERY can be extracted by providing the key as the third argument, for example, parse_url('http://facebook.com/path1/p.php?k1=v1&k2=v2#Ref1', 'QUERY', 'k1') returns 'v1'.

UDFParseUrl

string

printf(String format, Obj... args)

Returns the input formatted according to printf-style format strings formatstrings.

GenericUDFPrintf

stringquote(String text)

Returns the quoted string 

InputOutput
NULLNULL
DONT'DONT'
DON'T'DON\'T'

Status
colourGreen
titleNew
Includes escape character for any single quotes in Apache Hive 4.0.0

GenericUDFQuote

string

regexp_extract(string subject,string pattern,int index)

Returns the string extracted using the pattern. For example, regexp_extract('foothebar', 'foo(.*?)(bar)', 2) returns 'bar.' Note that some care is necessary in using predefined character classes: using '\s' as the second argument will match the letter s; '\\s' is necessary to match whitespace, etc. The 'index' parameter is the Java regex Matcher group() method index. 

UDFRegExpExtract

string

regexp_replace(string INITIAL_STRING,string PATTERN,string REPLACEMENT)

Returns the string resulting from replacing all substrings in INITIAL_STRING that match the java regular expression syntax defined in PATTERN with instances of REPLACEMENT. For example, regexp_replace("foobar", "oo|ar", "") returns 'fb.' Note that some care is necessary in using predefined character classes: using '\s' as the second argument will match the letter s; '\\s' is necessary to match whitespace, etc.

UDFRegExpReplace

string

repeat(string str,int n)

Repeats str in n times.

UDFRepeat

stringreplace(string A,string OLD,string NEW)Returns the string A with all non-overlapping occurrences of OLD replaced with NEW. Example: select replace("ababab", "abab", "Z"); returns "Zab".UDFReplace

string

reverse(string A)

Returns the reversed string.

UDFReverse

string

rpad(string str,int len,string pad)

Returns str, right-padded with pad to a length of len. If str is longer than len, the return value is shortened to len characters. In case of empty pad stringpadstring, the return value is null.

GenericUDFRpad

string

rtrim(string A)

Returns the string thestring resulting from trimming spaces from the end(right hand side) of A. For example, rtrim(' foobar ') results in ' foobar'.

GenericUDFRTrim

array<array<string>>

sentences(string str,string lang,string locale)

Tokenizes a string astring of natural language text into textinto words and sentences, where each sentence is broken at the appropriate sentence boundary and returned as an array of words. The 'lang' and 'locale' are optional arguments. For example, sentences('Hello there! How are you?') returns ( ("Hello", "there"), ("How", "are", "you") ).

GenericUDFSentences

string

space(int n)

Returns a string astring of n spaces.

UDFSpace

array

split(string str,string pat)

Splits str around pat (pat is a regular expression).

GenericUDFSplit

map<string,string>

str_to_map(text[, delimiter1, delimiter2])

Splits text into textinto key-value pairs using two delimiters. Delimiter1 separates text into textinto K-V pairs, and Delimiter2 splits each K-V pair. Default delimiters are ',' for delimiter1 and ':' for delimiter2.

GenericUDFStringToMap

string

substr(string|binary A,int start) substring(string|binary A,int start)

Returns the substring or slice of the byte array of A starting from start position till the end of string ofstring A. For example, substr('foobar', 4) results in 'bar'.

GenericUDFSubstringIndex



string

substr(string|binary A,int start,int len) substring(string|binary A,int start,int len)

Returns the substring or slice of the byte array of A starting from start position with length len. For example, substr('foobar', 4, 1) results in 'b'.

stringsubstring_index(string A,string delim,int count)Returns the substring from string A before count occurrences of the delimiter delim. If the count is positive, everything to the left of the final delimiter (counting from the left) is returned. If count is negative, everything to the right of the final delimiter (counting from the right) is returned. Substring_index performs a case-sensitive match when searching for delim. Example: substring_index('www.apache.org', '.', 2) = 'www.apache'.GenericUDFSubstringIndex

string

translate(string|char|varchar input,string|char|varchar from,string|char|varchar to)

Translates the input string by replacing the characters present in the fromstring with the corresponding characters in the tostring. This is similar to the translate function in PostgreSQL. If any of the parameters to this UDF are NULL, the result is NULL as well. 

GenericUDFTranslate

string

trim(string A)

Returns the string resulting from trimming spaces from both ends of A. For example, trim(' foobar ') results in 'foobar'

GenericUDFTrim

binary

unbase64(string str)

Converts the argument from a base 64 string 64string to BINARY.

UDFUnbase64

string

upper(string A) ucase(string A)

Returns the string resulting from converting all characters of A to upper case. For example, upper('fOoBaR') results in 'FOOBAR'.

GenericUDFUpper

stringinitcap(string A)Returns string, with the first letter of each word in uppercase, all other letters in lowercase. Words are delimited by whitespace.GenericUDFInitCap
intlevenshtein(string A,string B)Returns the Levenshtein distance between two strings. Example: levenshtein('kitten', 'sitting') results in 3.GenericUDFLevenshtein
stringsoundex(string A)Returns the soundex code of the string. Example: soundex('Miller') results in M460.GenericUDFSoundex

...

Return Type

Name(Signature)

Description

OSS

string

from_unixtime(bigint unixtime[,string pattern])

Converts a number of seconds since epoch (1970-01-01 00:00:00 UTC) to a string representing the timestamp of that moment in the current time zone(using config "hive.local.time.zone") using the specified pattern. If the pattern is missing the default is used ('uuuu-MM-dd HH:mm:ss' or yyyy-MM-dd HH:mm:ss'). Example: from_unixtime(0)=1970-01-01 00:00:00 (hive.local.time.zone=Etc/GMT)

Status
colourGreen
titleNew

As of Hive 4.0.0 the "hive.datetime.formatter" property can be used to control the underlying formatter implementation and as a consequence the accepted patterns and their behavior.  Earlier versions used https://docs.oracle.com/javase/8/docs/api/java/text/SimpleDateFormat.html as the underlying formatter.

GenericUDFFromUnixTime

bigint

unix_timestamp()

Gets the current Unix timestamp in seconds. This function is not deterministic and its value is not fixed for the scope of a query execution, therefore prevents proper optimization of queries - this has been deprecated since 2.0 in favour of CURRENT_TIMESTAMP constant.



GenericUDFUnixTimeStamp

bigint

unix_timestamp(string date)

Converts a DateTime string DateTimestring to unix time (seconds since epoch) using the default pattern(s). The default accepted patterns depend on the underlying formatter implementation. The datetime DateTime string does not contain a timezone so the conversion uses the local time zone as specified by "hive.local.time.zone" property. Returns null when the conversion fails. Example: unix_timestamp('2009-03-20 11:30:01') = 1237573801

Status
colourGreen
titleNew

As of Hive 4.0.0 the "hive.datetime.formatter" property can be used to control the underlying formatter implementation and as a consequence the accepted patterns and their behavior. Earlier versions used https://docs.oracle.com/javase/8/docs/api/java/text/SimpleDateFormat.html as the underlying formatter.

bigint

unix_timestamp(string date,string pattern)

Converts a datetime date-time string to unix time (seconds since epoch) using the specified pattern. The accepted patterns and their behavior depend on the underlying formatter implementation. Returns null when the conversion fails. Example: unix_timestamp('2009-03-20', 'uuuu-MM-dd') = 1237532400

Status
colourGreen
titleNew

As of Hive 4.0.0 the "hive.datetime.formatter" property can be used to control the underlying formatter implementation, and as a consequence the accepted patterns and their behavior.  Earlier versions used https://docs.oracle.com/javase/8/docs/api/java/text/SimpleDateFormat.html as the underlying formatter.

date

to_date(string timestamp)

Returns the date part of a timestamp date object. Example: to_date("1970-01-01 00:00:00") 

GenericUDFDate

int

year(string date)

Returns the year part of a date or a timestamp string: year("1970-01-01 00:00:00") = 1970, year("1970-01-01") = 1970.

UDFYear

int

quarter(date/timestamp/string)Returns the quarter of the year for a date, timestamp, or string in the range 1 to 4.  ExampleExample: quarter('2015-04-08') = 2.GenericUDFQuarter

int

month(string date)

Returns the month part of a date or a timestamp string. Example: month("1970-11-01 00:00:00") = 11, month("1970-11-01") = 11.

UDFMonth

int

day(string date) dayofmonth(date)

Returns the day part of a date or a timestamp string. Example: day("1970-11-01 00:00:00") = 1, day("1970-11-01") = 1.

UDFDayOfMonth

int

hour(string date)

Returns the hour of the timestamp: Example: hour('2009-07-30 12:58:59') = 12, hour('12:58:59') = 12.

UDFHour

int

minute(string date)

Returns the minute of the timestamp.

UDFMinute

int

second(string date)

Returns the second of the timestamp.

UDFSecond

int

weekofyear(string date)

Returns the week number of a timestamp string. Example: weekofyear("1970-11-01 00:00:00") = 44 or weekofyear("1970-11-01") = 44.

UDFWeekOfYear

int

extract(field FROM source)

Retrieve fields such as days or hours from the source. The source must be a date, timestamp,interval, or string that can be converted into convertedinto either a date or timestamp. Supported fields include day, dayofweek, hour, minute, month, quarter, second, week and year.

Examples:

  1. select extract(month from "2016-10-20") results in 10.

  2. select extract(hour from "2016-10-20 05:06:07") results in 5.

  3. select extract(dayofweek from "2016-10-20 05:06:07") results in 5.

  4. select extract(month from interval frominterval '1-3' year to month) results in 3.

  5. select extract(minute from interval frominterval '3 12:20:30' day to second) results in 20.


int

datediff(string enddate,string startdate)

Returns the number of days from startdate to end date. Example: datediff('2009-03-01', '2009-02-27') = 2.

GenericUDFDateDiff

date

date_add(date/timestamp/string startdate, tinyint/smallint/int days)

Adds a number of days to startdate. Example: date_add('2008-12-31', 1) = '2009-01-01'.

GenericUDFDateAdd

date

date_sub(date/timestamp/string startdate, tinyint/smallint/int days)

Subtracts a number of days to startdate: date_sub('2008-12-31', 1) = '2008-12-30'.

GenericUDFDateSub

timestamp

from_utc_timestamp({any primitive type} ts,string timezone)

Converts a timestamp* in UTC to a given timezone.

* timestamp is a primitive type, including timestamp/date, tinyint/smallint/int/bigint, float/double and decimal.

Fractional values are considered as seconds. Integer integer values are considered as milliseconds. For example, from_utc_timestamp(2592000.0,'PST'), from_utc_timestamp(2592000000,'PST') and from_utc_timestamp(timestamp '1970-01-30 16:00:00','PST') all return the timestamp 1970-01-30 08:00:00.

GenericUDFFromUtcTimestamp

timestamp

to_utc_timestamp({any primitive type} ts,string timezone)

Converts a timestamp* in a given timezone to UTC.

* timestamp is a primitive type, including timestamp/date, tinyint/smallint/int/bigint, float/double and decimal.

Fractional values are considered as seconds. Integer integer values are considered as milliseconds. For example, to_utc_timestamp(2592000.0,'PST'), to_utc_timestamp(2592000000,'PST') and to_utc_timestamp(timestamp '1970-01-30 16:00:00','PST') all return the timestamp 1970-01-31 00:00:00.

GenericUDFToUtcTimestamp

datecurrent_date

Returns the current date at the start of query evaluation. All calls of current_date within the same query return the same value.

GenericUDFCurrentDate

timestampcurrent_timestamp

Returns the current timestamp at the start of query evaluation. All calls of current_timestamp within the same query return the same value.

GenericUDFCurrentTimestamp

stringadd_months(string start_date,int num_months, output_date_format)

Returns the date that is num_months after start_date. start_date is a string, date or timestamp. num_months is an integeraninteger. If start_date is the last day of the month or if the resulting month has fewer days than the day component of start_date, then the result is the last day of the resulting month. Otherwise, the result has the same day component as start_date. The default output format is 'yyyy-MM-dd'.

Status
colourGreen
titleNew

Before Hive 4.0.0, the time part of the date is ignored. As of Hive 4.0.0, add_months supports an optional argument output_date_format, which accepts a String string that represents a valid date format for the output. This allows to retain the time format in the output.

For example :

add_months('2009-08-31', 1) returns '2009-09-30'.
add_months('2017-12-31 14:15:16', 2, 'YYYY-MM-dd HH:mm:ss') returns '2018-02-28 14:15:16'.

GenericUDFAddMonths

stringlast_day(string date)Returns the last day of the month to which the date belongs. date is is a string in the format 'yyyy-MM-dd HH:mm:ss' or 'yyyy-MM-dd'. The time part of the date is ignored!GenericUDFLastDay
stringnext_day(string start_date,string day_of_week)Returns the first date which is later than start_date and named as day_of_week.  start_date  is a stringastring/date/timestamp. day_of_week is 2 letters, 3 letters or full name of the day of the week (e.g. Mo, tue, FRIDAY). The time part of start_date is ignored. Example: next_day('2015-01-14', 'TU') = 2015-01-20.GenericUDFNextDay
stringtrunc(string date,string format)Returns date truncated to the unit specified by the format. Supported formats: MONTH/MON/MM, YEAR/YYYY/YY. Example: trunc('2015-03-17', 'MM') = 2015-03-01.GenericUDFTrunc
doublemonths_between(date1, date2)Returns the number of months between dates date1 and date2. If date1 is later than date2, then the result is positive. If date1 is earlier than date , then the result is negative. If date1 and date2 are either the same days of the month or both last days of months, then the result is always an integeraninteger. Otherwise, the UDF calculates the fractional portion of the result based on a 31-day month and considers the difference in time components date1 and date2. date1 and date2 type can be date, timestamp or string in the format 'yyyy-MM-dd' or 'yyyy-MM-dd HH:mm:ss'. The result is rounded to 8 decimal places. Example: months_between('1997-02-28 10:30:00', '1996-10-30') = 3.94959677GenericUDFMonthsBetween
stringdate_format(date/timestamp/string ts,string pattern)

Converts a date/timestamp/string to a value of string using the specified pattern. The accepted patterns and their behavior depend on the underlying formatter implementation. The pattern argument should be constant. Example: date_format('2015-04-08', 'y') = '2015'.

date_format can be used to implement other UDFs, e.g.:

  • dayname(date) is date_format(date, 'EEEE')
  • dayofyear(date) is date_format(date, 'D')

Status
colourGreen
titleNew

As of Hive 4.0.0 the "hive.datetime.formatter" property can be used to control the underlying formatter implementation and as a consequence the accepted patterns and their behavior.  Earlier versions used https://docs.oracle.com/javase/8/docs/api/java/text/SimpleDateFormat.html as the underlying formatter.

GenericUDFDateFormat

...

Return Type

Name (Signature)

Description

OSS

double

round(DOUBLE double a)

Returns the rounded BIGINT bigint value of a.

GenericUDFRound

double

round(DOUBLE double a, INT int d)

Returns a rounded to d decimal places.

doublebround(DOUBLE double a)Returns the rounded BIGINT bigint value of a using HALF_EVEN rounding mode. Also known as Gaussian rounding or bankers' rounding. Example: bround(2.5) = 2, bround(3.5) = 4.GenericUDFBRound
doublebround(DOUBLE double a, INT int d)Returns a rounded to d decimal places using HALF_EVEN rounding mode.  Example: bround(8.25, 1) = 8.2, bround(8.35, 1) = 8.4.

bigint

floor(DOUBLE double a)

Returns the maximum BIGINT bigint value that is equal to or less than a.

GenericUDFFloor

bigint

ceil(DOUBLE double a), ceiling(DOUBLE double a)

Returns the minimum BIGINT bigint value that is equal to or greater than a.

GenericUDFCeil

double

rand(), rand(INT seed)

Returns a random number (that changes from row to row) that is distributed uniformly from 0 to 1. Specifying the seed will make sure the generated random number sequence is deterministic.

UDFRand

double

exp(DOUBLE double a), exp(DECIMAL decimal a)

Returns ea where e is the base of the natural logarithm.

UDFExp

double

ln(DOUBLE double a), ln(DECIMAL decimal a)

Returns the natural logarithm of the argument a.

UDFLn

double

log10(DOUBLE double a), log10(DECIMAL decimal a)

Returns the base-10 logarithm of the argument a.

UDFLog10

double

log2(DOUBLE double a), log2(DECIMAL decimal a)

Returns the base-2 logarithm of the argument a. 

UDFLog2

double

log(DOUBLE double base, DOUBLE double a)

log(DECIMAL decimal base, DECIMAL decimal a)

Returns the base-base logarithm of the argument a.

UDFLog

double

pow(DOUBLE double a, DOUBLE double p), power(DOUBLE double a, DOUBLE double p)

Returns ap.

GenericUDFPower

double

sqrt(DOUBLE double a), sqrt(DECIMAL decimal a)

Returns the square root of a.

UDFSqrt

string

bin(BIGINT bigint a)

Returns the number in binary format.

UDFBin

string

hex(BIGINT bigint a) hex(STRING a) hex(BINARY a)

If the argument is an INT anint or binary, hex returns the number as a STRING string in hexadecimal format. Otherwise if the number is a STRINGstring, it converts each character into characterinto its hexadecimal representation and returns the resulting STRINGstring. 

UDFHex

binary

unhex(STRING a)

Inverse of hex. Interprets interprets each pair of characters as a hexadecimal number and converts to the byte representation of the number.

UDFUnhex

string

conv(BIGINT bigint num, INT int from_base, INT int to_base), conv(STRING num, INT int from_base, INT int to_base)

Converts a number from a given base to another.

UDFConv

double

abs(DOUBLE double a)

Returns the absolute value.

GenericUDFAbs

int or double

pmod(INT a, INT int b), pmod(DOUBLE double a, DOUBLE double b)

Returns the positive value of a mod b.

GenericUDFOPMod

double

sin(DOUBLE double a), sin(DECIMAL decimal a)

Returns the sine of a (a is in radians).

UDFSin

double

asin(DOUBLE double a), asin(DECIMAL decimal a)

Returns the arc sin of a if -1<=a<=1 or NULL otherwise. 

UDFAsin

double

cos(DOUBLE double a), cos(DECIMAL decimal a)

Returns the cosine of a (a is in radians). 

UDFCos

double

acos(DOUBLE double a), acos(DECIMAL decimal a)

Returns the arccosine of a if -1<=a<=1 or NULL otherwise.

UDFAcos

double

tan(DOUBLE double a), tan(DECIMAL decimal a)

Returns the tangent of a (a is in radians).

UDFTan

double

atan(DOUBLE double a), atan(DECIMAL decimal a)

Returns the arctangent of a.

UDFAtan

double

degrees(DOUBLE double a), degrees(DECIMAL decimal a)

Converts value of a from radians to degrees. 

UDFDegrees

double

radians(DOUBLE double a), radians(DOUBLE double a)

Converts value of a from degrees to radians. 

UDFRadians

int or double

positive(INT a), positive(DOUBLE double a)

Returns a.

GenericUDFOPPositive

int or double

negative(INT a), negative(DOUBLE double a)

Returns -a.

GenericUDFOPNegative

double or intorint

sign(DOUBLE double a), sign(DECIMAL decimal a)

Returns the sign of a as '1.0' (if a is positive) or '-1.0' (if a is negative), '0.0' otherwise. The decimal version returns INT returnsint instead of DOUBLEdouble. 

UDFSign

double

e()

Returns the value of e.

UDFE

double

pi()

Returns the value of pi.

UDFPI

bigintfactorial(INT a)Returns the factorial of a Valid a is [0..20].GenericUDFFactorial
doublecbrt(DOUBLE double a)Returns the cube root of a double value.GenericUDFCbrt

int

bigint

shiftleft(TINYINT|SMALLINT|INT a, INT int b)

shiftleft(BIGINT bigint a, INT int b)

Bitwise left shift. Shifts a b positions to the left.

Returns int Returnsint for tinyint, smallint and int andint a. Returns bigint for bigint a.

UDFOPBitShiftLeft

int

bigint

shiftright(TINYINT|SMALLINT|INT a, INT int b)

shiftright(BIGINT bigint a, INT int b)

Bitwise right shift. Shifts a b positions to the right.

Returns int Returnsint for tinyint, smallint and int andint a. Returns bigint for bigint a.

UDFOPBitShiftRight

int

bigint

shiftrightunsigned(TINYINT|SMALLINT|INT a, INT int b),

shiftrightunsigned(BIGINT bigint a, INT int b)

Bitwise unsigned right shift. Shifts a b positions to the right.

Returns int Returnsint for tinyint, smallint and int andint a. Returns bigint for bigint a.

UDFOPBitShiftRightUnsigned

Tgreatest(T v1, T v2, ...)Returns the greatest value of the list of values. Fixed to return NULL when one or more arguments are NULL, and strict type restriction relaxed, consistent with ">" operator.GenericUDFGreatest
Tleast(T v1, T v2, ...)Returns the least value of the list of values. Fixed to return NULL when one or more arguments are NULL, and strict type restriction relaxed, consistent with "<" operator.GenericUDFLeast
intwidth_bucket(NUMERIC expr, NUMERIC min_value, NUMERIC max_value, INT int num_buckets)

Returns an integer aninteger between 0 and num_buckets+1 by mapping expr into exprinto the ith equally sized bucket. Buckets are made by dividing [min_value, max_value]into equally sized regions. If expr < min_value, return 1, if expr > max_value return num_buckets+1. See https://docs.oracle.com/cd/B19306_01/server.102/b14200/functions214.htm

GenericUDFWidthBucket

...

Return Type

Name(Signature)

Description

OSS

binary

binary(string|binary)

Casts the parameter into parameterinto a binary.

GenericUDFBaseBinary

Expected "=" to follow "type"

cast(expr as <type>)

Converts the results of the expression expr to <type>. For example, cast('1' as BIGINTbigint) will convert the string '1' to its integral itsintegral representation. A null is returned if the conversion does not succeed. If cast(expr as boolean) Hive returns true for a non-empty string.


...

Return Type

Name(Signature)

Description


varies

java_method(class, method[, arg1[, arg2..]])

Synonym for reflect.


varies

reflect(class, method[, arg1[, arg2..]])

Calls a Java method by matching the argument signature, using reflection. See Reflect (Generic) UDF for examples.

GenericUDFReflect

int

hash(a1[, a2...])

Returns a hash value of the arguments. 

GenericUDFHash

stringcurrent_user()Returns current user name from the configured authenticator manager. Could be the same as the user provided when connecting, but with some authentication managers (for example HadoopDefaultAuthenticator) it could be different.GenericUDFCurrentUser
stringlogged_in_user()Returns the current user name from the session state. This is the username provided when connecting to Hive.GenericUDFLoggedInUser
stringcurrent_database()Returns current database name.GenericUDFCurrentDatabase
stringmd5(string/binary)Calculates an MD5 128-bit checksum for the string or binary. The value is returned as a string of 32 hex digits, or NULL if the argument was NULL. Example: md5('ABC') = '902fbdd2b1df0c4f70b4a5d23525e932'.UDFMd5
string

sha1(string/binary)

sha(string/binary)

Calculates the SHA-1 digest for string or binary and returns the value as a hex string.
Example: sha1('ABC') = '3c01bdbb26f358bab27f267924aa2c9a03fcfdb8'.		UDFSha1
bigintcrc32(string/binary)Computes a cyclic redundancy check value for string or binary argument and returns bigint value. Example: crc32('ABC') = 2743272264.UDFCrc32
stringsha2(string/binary,int)Calculates the SHA-2 family of hash functions (SHA-224, SHA-256, SHA-384, and SHA-512). The first argument is the string or binary to be hashed. The second argument indicates the desired bit length of the result, which must have a value of 224, 256, 384, 512, or 0 (which is equivalent to 256). SHA-224 is supported starting from Java 8. If either argument is NULL or the hash length is not one of the permitted values, the return value is NULL. Example: sha2('ABC', 256) = 'b5d4045c3f466fa91fe2cc6abe79232a1a57cdf104f7a26e716e0a1e2789df78'.GenericUDFSha2
binaryaes_encrypt(input stringinputstring/binary, key stringkeystring/binary)Encrypt input using AES. Key lengths of 128, 192 or 256 bits can be used. 192 and 256 bits keys can be used if Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files are installed. If either argument is NULL or the key length is not one of the permitted values, the return value is NULL.
Example: base64(aes_encrypt('ABC', '1234567890123456')) = 'y6Ss+zCYObpCbgfWfyNWTw=='.		GenericUDFAesEncrypt
binaryaes_decrypt(input binary, key stringkeystring/binary)Decrypt input using AES. Key lengths of 128, 192 or 256 bits can be used. 192 and 256 bits keys can be used if Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files are installed. If either argument is NULL or the key length is not one of the permitted values, the return value is NULL.
Example: aes_decrypt(unbase64('y6Ss+zCYObpCbgfWfyNWTw=='), '1234567890123456') = 'ABC'.		GenericUDFAesDecrypt
stringversion()Returns the Hive version. The string contains 2 fields, the first being a build number and the second being a build hash. Example: "select version();" might return "2.1.0.2.5.0.0-1245 r027527b9c5ce1a3d7d0b6d2e6de2378fb0c39232". Actual results will depend on your build.UDFVersion
bigintsurrogate_key([write_id_bits, task_id_bits])Automatically generate numerical Ids for rows as you enter data into a table. Can only be used as the default value for acid or insert-only tables.GenericUDFSurrogateKey

...