THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
...
REPLACE COLUMNS removes all existing columns and adds the new set of columns. This can be done only for tables with native serde (DynamicSerDe or , MetadataTypedColumnsetSerDe, LazySimpleSerDe and ColumnarSerDe). Refer to SerDe section of User Guide for more information. REPLACE COLUMNS can also be used to drop columns. For example:
...