Oleg Smirnov 5027cb2b74 MDEV-29662 Replace same values in 'IN' list with an equality ...

If all elements in the list of 'IN' or 'NOT IN' clause are equal
and there are no NULLs then clause
-  "a IN (e1,..,en)" can be converted to "a = e1"
-  "a NOT IN (e1,..,en)" can be converted to "a <> e1".
This means an object of Item_func_in can be replaced with an object
of Item_func_eq for IN (e1,..,en) clause and Item_func_ne for
NOT IN (e1,...,en). Such a replacement allows the optimizer to choose
a better execution plan

2022-10-26 11:01:56 +07:00

91 KiB

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