# Is aj supposed to have a dependance on the order of the join columns?

**URL:** <https://forum.kx.com/t/is-aj-supposed-to-have-a-dependance-on-the-order-of-the-join-columns/5991>\
**Category:** Community Support\
**Tags:** kdb-and-q\
**Created:** [March 16, 2009, 10:26pm UTC](https://forum.kx.com/t/is-aj-supposed-to-have-a-dependance-on-the-order-of-the-join-columns/5991 "2009-03-16T22:26:00Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![annakh71](https://avatars.discourse-cdn.com/v4/letter/a/3be4f8/32.png) [@annakh71](https://forum.kx.com/u/annakh71)\
**Post date:** [March 16, 2009, 10:26pm UTC](https://forum.kx.com/t/is-aj-supposed-to-have-a-dependance-on-the-order-of-the-join-columns/5991/1 "2009-03-16T22:26:00Z")

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Subject says it all. The book does not hint at it but it looks like itdoes.

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**Author:** ![annakh71](https://avatars.discourse-cdn.com/v4/letter/a/3be4f8/32.png) [@annakh71](https://forum.kx.com/u/annakh71)\
**Post date:** [March 16, 2009, 11:15pm UTC](https://forum.kx.com/t/is-aj-supposed-to-have-a-dependance-on-the-order-of-the-join-columns/5991/2 "2009-03-16T23:15:00Z")

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To answer my own question, this seems to be a symptom of an unsorteddate/time column; aj assumes it is sorted.

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**Author:** ![Chris\_Burke1](https://avatars.discourse-cdn.com/v4/letter/c/e9bcb4/32.png) [@Chris\_Burke1](https://forum.kx.com/u/Chris_Burke1)\
**Post date:** [March 17, 2009, 1:07am UTC](https://forum.kx.com/t/is-aj-supposed-to-have-a-dependance-on-the-order-of-the-join-columns/5991/3 "2009-03-17T01:07:00Z")

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Yes, the second table needs to be sorted. See also the discussion insection 9 of [http://kx.com/q/d/q.htm](http://kx.com/q/d/q.htm) .On Mar 17, 7:15?am, annakh7 \<anna…\> wrote:\> To answer my own question, this seems to be a symptom of an unsorted\> date/time column; aj assumes it is sorted.\</anna…\>