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MDEV-34123 CONCAT Function Returns Unexpected Empty Set in Query

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Search conditions were evaluated using val_int(), which was wrong.
Fixing the code to use val_bool() instead.

Details:
- Adding a new item_base_t::IS_COND flag which marks Items used
  as <search condition> in WHERE, HAVING, JOIN ON, CASE WHEN clauses.
  The flag is at the parse time.
  These expressions must be evaluated using val_bool() rather than val_int().

  Note, the optimizer creates more Items which are used as search conditions.
  Most of these items are not marked with IS_COND yet. This is OK for now,
  but eventually these Items can also be fixed to have the flag.

- Adding a method Item::is_cond() which tests if the Item has the IS_COND flag.

- Implementing Item_cache_bool. It evaluates the cached expression using
  val_bool() rather than val_int().
  Overriding Type_handler_bool::Item_get_cache() to create Item_cache_bool.

- Implementing Item::save_bool_in_field(). It uses val_bool() rather than
  val_int() to evaluate the expression.

- Implementing Type_handler_bool::Item_save_in_field()
  using Item::save_bool_in_field().

- Fixing all Item_bool_func descendants to implement a virtual val_bool()
  rather than a virtual val_int().

- To find places where val_int() should be fixed to val_bool(), a few
  DBUG_ASSERT(!is_cond()) where added into val_int() implementations
  of selected (most frequent) classes:

  Item_field
  Item_str_func
  Item_datefunc
  Item_timefunc
  Item_datetimefunc
  Item_cache_bool
  Item_bool_func
  Item_func_hybrid_field_type
  Item_basic_constant descendants

- Fixing all places where DBUG_ASSERT() happened during an "mtr" run
  to use val_bool() instead of val_int().
This commit is contained in:
Alexander Barkov
2024-05-14 09:19:34 +04:00
committed by Oleksandr Byelkin
parent 6f6c1911dc
commit a931da82fa
52 changed files with 2098 additions and 151 deletions
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4
sql/sql_parse.cc
View File

@@ -9190,7 +9190,11 @@ Item *normalize_cond(THD *thd, Item *cond)
Item::Type type= cond->type();
if (type == Item::FIELD_ITEM || type == Item::REF_ITEM)
{
item_base_t is_cond_flag= cond->base_flags & item_base_t::IS_COND;
cond->base_flags&= ~item_base_t::IS_COND;
cond= new (thd->mem_root) Item_func_ne(thd, cond, new (thd->mem_root) Item_int(thd, 0));
if (cond)
cond->base_flags|= is_cond_flag;
}
else
{