Marios Trivyzas da3d8fb5b7

SQL: Fix issue with wrong NULL optimization (#37124) ...

Logical operators OR and AND as well as conditional functions
(COALESCE, LEAST, GREATEST, etc.) cannot be folded to NULL if one
of their children is NULL as is the case for most of the functions.
Therefore, their nullable() implementation cannot return true. On
the other hand they cannot return false as if they're wrapped within
an IS NULL or IS NOT NULL expression, the expression will be folded
to false and true respectively leading to wrong results.

Change the signature of nullable() method and add a third value UKNOWN
to handle these cases.

Fixes: #35872

2019-01-06 18:29:34 +02:00

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main

SQL: Fix issue with wrong NULL optimization (#37124)

2019-01-06 18:29:34 +02:00

test

SQL: Fix issue with wrong NULL optimization (#37124)

2019-01-06 18:29:34 +02:00