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Comment: finish adding examples for from_utc_timestamp() & to_utc_timestamp() from HIVE-2974 (unwanted save)

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Return Type

Name(Signature)

Description

string

from_unixtime(bigint unixtime[, string format])

Converts the number of seconds from unix epoch (1970-01-01 00:00:00 UTC) to a string representing the timestamp of that moment in the current system time zone in the format of "1970-01-01 00:00:00".

bigint

unix_timestamp()

Gets current Unix timestamp in seconds.

bigint

unix_timestamp(string date)

Converts time string in format yyyy-MM-dd HH:mm:ss to Unix timestamp (in seconds), using the default timezone and the default locale, return 0 if fail: unix_timestamp('2009-03-20 11:30:01') = 1237573801

bigint

unix_timestamp(string date, string pattern)

Convert time string with given pattern (see [http://docs.oracle.com/javase/tutorial/i18n/format/simpleDateFormat.html]) to Unix time stamp (in seconds), return 0 if fail: unix_timestamp('2009-03-20', 'yyyy-MM-dd') = 1237532400.

string

to_date(string timestamp)

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

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.

int

month(string date)

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

int

day(string date) dayofmonth(date)

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

int

hour(string date)

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

int

minute(string date)

Returns the minute of the timestamp.

int

second(string date)

Returns the second of the timestamp.

int

weekofyear(string date)

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

int

datediff(string enddate, string startdate)

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

string

date_add(string startdate, int days)

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

string

date_sub(string startdate, int days)

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

timestamp

from_utc_timestamp(timestamp, string timezone)

Assumes given timestamp is UTC and converts to given timezone (as of Hive 0.8.0). For example, from_utc_timestamp('1970-01-01 08:00:00','PST') returns " 1970-01-01 00:00:00".

timestamp

to_utc_timestamp(timestamp, string timezone)

Assumes given timestamp is in given timezone and converts to UTC (as of Hive 0.8.0). For example, to_utc_timestamp('1970-01-01 00:00:00','PST') returns 1970-01-01 08:00:00.

Conditional Functions

Return Type

Name(Signature)

Description

T

if(boolean testCondition, T valueTrue, T valueFalseOrNull)

Returns valueTrue when testCondition is true, returns valueFalseOrNull otherwise.

T

COALESCE(T v1, T v2, ...)

Returns the first v that is not NULL, or NULL if all v's are NULL.

T

CASE a WHEN b THEN c [WHEN d THEN e]* [ELSE f] END

When a = b, returns c; when a = d, returns e; else returns f.

T

CASE WHEN a THEN b [WHEN c THEN d]* [ELSE e] END

When a = true, returns b; when c = true, returns d; else returns e.

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