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MDEV-19520 Extend condition normalization to include 'NOT a'

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Having Item_func_not items in item trees breaks assumptions during the
optimization phase about transformation possibilities in fix_fields().
Remove Item_func_not by extending normalization during parsing.

Reviewed by Oleksandr Byelkin (sanja@mariadb.com)
This commit is contained in:
Rex
2024-04-30 10:39:20 +11:00
parent d9dd673fee
commit d513a4ce74
3 changed files with 40 additions and 0 deletions
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16
sql/sql_parse.cc
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@@ -9234,6 +9234,7 @@ push_new_name_resolution_context(THD *thd,
/**
Fix condition which contains only field (f turns to f <> 0 )
or only contains the function NOT field (not f turns to f == 0)
@param cond The condition to fix
@@ -9249,6 +9250,21 @@ Item *normalize_cond(THD *thd, Item *cond)
{
cond= new (thd->mem_root) Item_func_ne(thd, cond, new (thd->mem_root) Item_int(thd, 0));
}
else
{
if (type == Item::FUNC_ITEM)
{
Item_func *func_item= (Item_func *)cond;
if (func_item->functype() == Item_func::NOT_FUNC)
{
Item *arg= func_item->arguments()[0];
if (arg->type() == Item::FIELD_ITEM ||
arg->type() == Item::REF_ITEM)
cond= new (thd->mem_root) Item_func_eq(thd, arg,
new (thd->mem_root) Item_int(thd, 0));
}
}
}
}
return cond;
}