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From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Update of "Hive/LanguageManual/UDF" by PaulYang
Date Tue, 05 Jan 2010 00:23:04 GMT
Dear Wiki user,

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The "Hive/LanguageManual/UDF" page has been changed by PaulYang.


- == Built in Aggregate Functions (UDAF) ==
+ == Built-in Aggregate Functions (UDAF) ==
  The following are built-in aggregate functions are supported in Hive:
  ||<10%> '''Return Type''' ||<10%> '''Name(Signature)''' || '''Description'''
  ||BIGINT ||count(1), count(DISTINCT col [, col]...) ||count(1) returns the number of members
in the group, whereas the count(DISTINCT col) gets the count of distinct values of the columns
in the group ||
@@ -221, +221 @@

  ||double ||min(col) ||Returns the minimum of the column in the group ||
  ||double ||max(col) ||Returns the maximum value of the column n the group ||
- == Built in Table Generating Functions (UDTF) ==
+ == Built-in Table-Generating Functions (UDTF) ==
+ <<Anchor(UDTF)>>
  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 to
multiple output rows. Currently, the only table-generating function is explode(), which takes
in an array as an input and outputs the elements of the array as separate rows. UDTF's can
be used in the SELECT expression list and as a part of LATERAL VIEW.
  An example use of explode() in the SELECT expression list is as follows:

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