ReQL command: innerJoin

Command syntax

sequence.innerJoin(otherSequence, predicate_function) → stream
array.innerJoin(otherSequence, predicate_function) → array

Description

Returns an inner join of two sequences.

The returned sequence represents an intersection of the left-hand sequence and the right-hand sequence: each row of the left-hand sequence will be compared with each row of the right-hand sequence to find all pairs of rows which satisfy the predicate. Each matched pair of rows of both sequences are combined into a result row. In most cases, you will want to follow the join with zip to combine the left and right results.

Note that innerJoin is slower and much less efficient than using eqJoin or concatMap with getAll. You should avoid using innerJoin in commands when possible.

Example: Return a list of all matchups between Marvel and DC heroes in which the DC hero could beat the Marvel hero in a fight.

r.table('marvel').innerJoin(r.table('dc'), function(marvelRow, dcRow) {
    return marvelRow('strength').lt(dcRow('strength'))
}).zip().run(conn, callback)

(Compare this to an outerJoin with the same inputs and predicate, which would return a list of all Marvel heroes along with any DC heroes with a higher strength.)

Related commands

• outerJoin
• eqJoin
• zip

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