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Version: v1.2.0



join combine data from two inputs using a join predicate


( => left path => right path )
| [anti|inner|left|right] join on <left-key>=<right-key> [<field>:=<right-expr>, ...]


The join operator combines records from two inputs based on whether the <left-key> expression (evaluated in the context of the left input) is equal to the <right-key> expression (evaluated in the context of the right input) omitting values where there is no match (or including them in the case of anti join).

The available join types are:

  • inner - output only values that match
  • left - output all left values with merged components from <right-expr>
  • right - output as a left join but with the roles of the inputs and <right-expr> reversed
  • anti - output left values whose left key does not have a matching right key

For anti join, the <right-expr> is undefined and thus cannot be specified.

Currently, only exact equi-join is supported and the inputs must be sorted in ascending order by their respective keys. Also, the join keys must be field expressions. A future version of join will not require sorted inputs and will have more flexible join expressions.


The join tutorial includes several examples.