[HIVE-650] [UDAF] implement GROUP_CONCAT(expr)

• Type: New Feature
• Status: Resolved
• Priority: Major
• Resolution: Duplicate
• Assignee: Unassigned
• Reporter: Min Zhou
• Created: 17/Jul/09 06:18
• Updated: 24/Nov/10 20:00
• Resolved: 24/Nov/10 20:00

Description

It's a very useful udaf for us.
http://dev.mysql.com/doc/refman/5.0/en/group-by-functions.html#function_group-concat

GROUP_CONCAT(expr)

This function returns a string result with the concatenated non-NULL values from a group. It returns NULL if there are no non-NULL values. The full syntax is as follows:

GROUP_CONCAT([DISTINCT] expr [,expr ...]
[ORDER BY

{unsigned_integer | col_name | expr}

[ASC | DESC] [,col_name ...]]
[SEPARATOR str_val])

Issue Links

• duplicates: HIVE-707 add group_concat