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The following page has been changed by RaghothamMurthy: http://wiki.apache.org/hadoop/Hive/LanguageManual/Select ------------------------------------------------------------------------------ SELECT col1, COUNT(col2), sum(col3) FROM t1 GROUP BY col1 }}} - * [wiki:Self:Hive/LanguageManual/ClusterBy Cluster 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 }}} - * [wiki:Self:Hive/LanguageManual/ClusterBy Distribute By and Sort By] + * 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, col2 + 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.
