[hive] 함수 설명 보기

hive 함수를 보려면 다음 명령어를 사용한다.

SHOW FUNCTIONS; 

DESCRIBE FUNCTION 함수이름;

DESCRIBE FUNCTION EXTENDED 함수이름;

 

예)

> DESCRIBE FUNCTION  xpath_string;

OK

xpath_string(xml, xpath) - Returns the text contents of the first xml node that matches the xpath expression

Time taken: 0.006 seconds, Fetched: 1 row(s)

> DESCRIBE FUNCTION EXTENDED xpath_string;

OK

xpath_string(xml, xpath) - Returns the text contents of the first xml node that matches the xpath expression

Example:

  > SELECT xpath_string('<a><b>b</b><c>cc</c></a>','a/c') FROM src LIMIT 1;

  'cc'

  > SELECT xpath_string('<a><b>b1</b><b>b2</b></a>','a/b') FROM src LIMIT 1;

  'b1'

  > SELECT xpath_string('<a><b>b1</b><b>b2</b></a>','a/b[2]') FROM src LIMIT 1;

  'b2'

  > SELECT xpath_string('<a><b>b1</b><b>b2</b></a>','a') FROM src LIMIT 1;

  'b1b2'

Time taken: 0.01 seconds, Fetched: 10 row(s)