ok. And the jira url is https://issues.apache.org/jira/browse/CALCITE-2102
2017-12-20 13:08 GMT+08:00 Julian Hyde <[email protected]>: > I agree. The Sort RelNode (or better, RelCollation) should have a > constraint that prevents this. And SqlToRelConverter (or perhaps > RelBuilder) should ignore sort keys that have appeared earlier in the key. > > Can you log a jira case please. > > Julian > > > On Dec 19, 2017, at 5:56 PM, John Fang <[email protected]> wrote: > > > > Hi all, > > I test the query "SELECT a, c FROM MyTable ORDER BY a DESC, a DESC". > > And the collation of LogicalSort is "[0 DESC, 0 DESC]" , thus it will > sort > > by the repeater fields. I think the calcite should > > removal the repeated fields, make the LogicalSort whose collation is "[0 > > DESC]" be more reasonable. > > -- > > > > Regards > > > > John Fang > -- Regards John Fang
