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From lincoln-lil <...@git.apache.org>
Subject [GitHub] flink issue #3141: [FLINK-5520] [table] Disable outer joins with non-equalit...
Date Thu, 19 Jan 2017 16:39:24 GMT
Github user lincoln-lil commented on the issue:

    @fhueske when I add more test cases for "outer joins" with local predicates, I found different
limitations between tableAPI and SQL, e.g., "SELECT c, g FROM Table3 left outer join Table5
on a = d AND e < 3" is valid, but dsFromTuple3.leftOuterJoin(dsFromTuple5, 'a === 'd &&
'e < 3) is invalid, because validation in Join node sees original join predicates and validates
simply, while in DataSetJoinRule the join predicates could be pruned according to the equivalence
in relational algebra. 
    I have a question, should we keep the tableAPI consistent with SQL? If so, the validation
in tableAPI will be much more complex, and it reminds me the previous discussion about validation
either in one or two places.  Or just maintain the current implementation unchanged, because
we will add support for both FLINK-5498 and FLINK-5511 soon, then these differences will be
    What do you think ?

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