Dear Wiki user, You have subscribed to a wiki page or wiki category on "Hadoop Wiki" for change notification.
The following page has been changed by ZhengShao: http://wiki.apache.org/hadoop/Hive/LanguageManual/Select ------------------------------------------------------------------------------ WHERE page_views.date >= '2008-03-01' AND page_views.date <= '2008-03-31' }}} - * [wiki:Self:Hive/LanguageManual/GroupBy Group By] + * See also [wiki:Self:Hive/LanguageManual/GroupBy Group By] - {{{ - SELECT col1, COUNT(col2), sum(col3) FROM t1 GROUP BY col1 - }}} + * See also [wiki:Self:Hive/LanguageManual/SortBy Sort By / Cluster By / Distribute By / Order By] - * Cluster By. This construct is used mainly with the [wiki:Self:Hive/LanguageManual/Transform MAP and REDUCE] clauses. But, it is sometimes useful in SELECT statements if there is a need to partition and sort the output of a query for subsequent queries. - {{{ - SELECT col1, col2 FROM t1 CLUSTER BY col1 - }}} - * Distribute By and Sort By. These constructs are mainly used with the [wiki:Self:Hive/LanguageManual/Transform MAP and REDUCE] clauses. But, they can be used to distribute and sort the output of a query. Sort By also supports ASC and DESC for ascending and descending order of sorting, but defaults to ASC if nothing is specified. - {{{ - SELECT col1, col2 FROM t1 DISTRIBUTE BY col1 - - SELECT col1, col2 FROM t1 DISTRIBUTE BY col1 SORT BY col1 ASC, col2 DESC - }}} - - * Order By - Hive currently does not support ORDER BY. A similar effect can be gotten by using SORT BY and setting number of reducers to 1. The following query does ORDER BY col1. Note however that this query can take a long time if the size of t1 is large since there is only one reducer. - {{{ - SET mapred.reduce.tasks = 1 - SELECT * FROM t1 SORT BY col1 - }}} - - * Having - Hive currently does not support HAVING clause. A similar effect can be gotten by using a subquery. For example, + * Having - Hive currently does not support HAVING clause. A similar effect can be gotten by using a subquery. For example, {{{ SELECT col1 FROM t1 GROUP BY col1 HAVING SUM(col2) > 10 }}}
