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Comment: typo fix

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  • LEFT SEMI JOIN implements the uncorrelated IN/EXISTS subquery semantics in an efficient way. As of Hive 0.13 the IN/NOT IN/EXISTS/NOT EXISTS operators are supported using subqueries so most of these JOINs don't have to be performed manually anymore. The restrictions of using LEFT SEMI JOIN is are that the right-hand-side table should only be referenced in the join condition (ON-clause), but not in WHERE- or SELECT-clauses etc.

    Code Block
      SELECT a.key, a.value
  FROM a
  WHERE a.key in
   (SELECT b.key
    FROM B);

    can be rewritten to:

    Code Block
       SELECT a.key, a.val
   FROM a LEFT SEMI JOIN b ON (a.key = b.key)

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