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From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Update of "Hive/LanguageManual/LateralView" by JohnSichi
Date Wed, 31 Mar 2010 19:22:48 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Hadoop Wiki" for change notification.

The "Hive/LanguageManual/LateralView" page has been changed by JohnSichi.
http://wiki.apache.org/hadoop/Hive/LanguageManual/LateralView?action=diff&rev1=4&rev2=5

--------------------------------------------------

  
  == Description ==
  
- Lateral view is used in conjunction with user-defined table generating functions such as
explode(). As mentioned in [wiki:Self:Hive/LanguageManual/UDF#UDTF], a UDTF generates one
or more output rows for each input row. A lateral view first applies the UDTF to each row
of base table and then joins resulting output rows to the input rows to form a virtual table
having the supplied table alias. 
+ Lateral view is used in conjunction with user-defined table generating functions such as
explode(). As mentioned in [[Hive/LanguageManual/UDF#UDTF]], a UDTF generates one or more
output rows for each input row. A lateral view first applies the UDTF to each row of base
table and then joins resulting output rows to the input rows to form a virtual table having
the supplied table alias. 
  
  == Example ==
  
@@ -27, +27 @@

  
  and the user would like to count the total number of times an ad appears across all pages.
  
- A lateral view with explode() [wiki:Self:Hive/LanguageManual/UDF#explode] can be used to
convert adid_list into separate rows using the query:
+ A lateral view with explode() [[Hive/LanguageManual/UDF#explode]] can be used to convert
adid_list into separate rows using the query:
  {{{
  SELECT pageid, adid FROM pageAds LATERAL VIEW explode(adid_list) adTable AS adid;
  }}}

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