Sergei Petrunia 7259b299a5 MDEV-27382: OFFSET is ignored when combined with DISTINCT ...

A query in form

  SELECT DISTINCT expr_that_is_inferred_to_be_const LIMIT 0 OFFSET n

produces one row when it should produce none. The issue was in
JOIN_TAB::remove_duplicates() in the piece of logic that tried to
avoid duplicate removal for such cases but didn't account for possible
"LIMIT 0".

Fixed by making Select_limit_counters::set_limit() change OFFSET to 0
when LIMIT is 0.

2022-01-19 14:04:10 +03:00

2.1 KiB

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