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Fixed that NULL and 0 returns 0 instead of NULL

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This is coded to not cause a speed impact on top level AND expressions where we don't care if an AND expression returns 0 or NULL


mysql-test/r/bdb.result:
  Fix results after serges last patch
mysql-test/r/innodb.result:
  Fix results after serges last patch
mysql-test/r/null.result:
  Update for new AND handling of NULL
scripts/mysqld_safe.sh:
  Fix 'isroot' test to work even if user is not root
sql/item.h:
  Fixed that NULL and 0 returns 0 instead of NULL
sql/item_cmpfunc.cc:
  Fixed that NULL and 0 returns 0 instead of NULL
sql/item_cmpfunc.h:
  Fixed that NULL and 0 returns 0 instead of NULL
sql/sql_base.cc:
  Fixed that NULL and 0 returns 0 instead of NULL
sql/sql_parse.cc:
  Fixed that NULL and 0 returns 0 instead of NULL
sql/sql_select.cc:
  Fixed that NULL and 0 returns 0 instead of NULL
sql/sql_yacc.yy:
  Fixed that NULL and 0 returns 0 instead of NULL
This commit is contained in:
unknown
2002-11-11 15:57:35 +02:00
parent 1b6548d54d
commit 3165440cde
13 changed files with 148 additions and 32 deletions
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44
sql/item_cmpfunc.cc
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@ -26,8 +26,8 @@
/*
Test functions
These returns 0LL if false and 1LL if true and null if some arg is null
'AND' and 'OR' never return null
Most of these returns 0LL if false and 1LL if true and
NULL if some arg is NULL.
*/
longlong Item_func_not::val_int()
@ -533,6 +533,7 @@ Item_func_if::fix_length_and_dec()
else
cached_result_type=arg1_type; // Should be INT_RESULT
}
args[0]->top_level_item();
}
@ -1128,6 +1129,8 @@ Item_cond::fix_fields(THD *thd,TABLE_LIST *tables)
const_item_cache&=item->const_item();
if (item->maybe_null)
maybe_null=1;
if (abort_on_null)
item->top_level_item();
}
if (thd)
thd->cond_count+=list.elements;
@ -1196,28 +1199,41 @@ void Item_cond::print(String *str)
str->append(')');
}
/*
Evalution of AND(expr, expr, expr ...)
NOTES:
abort_if_null is set for AND expressions for which we don't care if the
result is NULL or 0. This is set for:
- WHERE clause
- HAVING clause
- IF(expression)
RETURN VALUES
1 If all expressions are true
0 If all expressions are false or if we find a NULL expression and
'abort_on_null' is set.
NULL if all expression are either 1 or NULL
*/
longlong Item_cond_and::val_int()
{
List_iterator_fast<Item> li(list);
Item *item;
null_value= 0;
while ((item=li++))
{
if (item->val_int() == 0)
{
/*
TODO: In case of NULL, ANSI would require us to continue evaluation
until we get a FALSE value or run out of values; This would
require a lot of unnecessary evaluation, which we skip for now
*/
null_value=item->null_value;
return 0;
if (abort_on_null || !(null_value= item->null_value))
return 0; // return FALSE
}
}
null_value=0;
return 1;
return null_value ? 0 : 1;
}
longlong Item_cond_or::val_int()
{
List_iterator_fast<Item> li(list);
@ -1260,15 +1276,15 @@ longlong Item_cond_or::val_int()
Item *and_expressions(Item *a, Item *b, Item **org_item)
{
if (!a)
return (*org_item= (Item*) b);
return (*org_item= b);
if (a == *org_item)
{
Item_cond *res;
if ((res= new Item_cond_and(a, (Item*) b)))
if ((res= new Item_cond_and(a, b)))
res->used_tables_cache= a->used_tables() | b->used_tables();
return res;
}
if (((Item_cond_and*) a)->add((Item*) b))
if (((Item_cond_and*) a)->add(b))
return 0;
((Item_cond_and*) a)->used_tables_cache|= b->used_tables();
return a;