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configure.in:
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sql/field.cc:
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sql/ha_ndbcluster.cc:
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sql/item.h:
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sql/item_cmpfunc.h:
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sql/item_func.cc:
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sql/item_strfunc.cc:
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sql/item_timefunc.cc:
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tests/mysql_client_test.c:
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This commit is contained in:
unknown
2006-06-18 14:56:35 +04:00
parent 60a9c875e8 9ec3f63f7e
commit 610b1a4ebd
51 changed files with 1061 additions and 231 deletions
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156
sql/item_cmpfunc.cc
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@@ -63,25 +63,144 @@ static void agg_result_type(Item_result *type, Item **items, uint nitems)
}
/*
Aggregates result types from the array of items.
SYNOPSIS:
agg_cmp_type()
thd thread handle
type [out] the aggregated type
items array of items to aggregate the type from
nitems number of items in the array
DESCRIPTION
This function aggregates result types from the array of items. Found type
supposed to be used later for comparison of values of these items.
Aggregation itself is performed by the item_cmp_type() function.
NOTES
Aggregation rules:
If all items are constants the type will be aggregated from all items.
If there are some non-constant items then only types of non-constant
items will be used for aggregation.
If there are DATE/TIME fields/functions in the list and no string
fields/functions in the list then:
The INT_RESULT type will be used for aggregation instead of original
result type of any DATE/TIME field/function in the list
All constant items in the list will be converted to a DATE/TIME using
found field or result field of found function.
Implementation notes:
The code is equivalent to:
1. Check the list for presence of a STRING field/function.
Collect the is_const flag.
2. Get a Field* object to use for type coercion
3. Perform type conversion.
1 and 2 are implemented in 2 loops. The first searches for a DATE/TIME
field/function and checks presence of a STRING field/function.
The second loop works only if a DATE/TIME field/function is found.
It checks presence of a STRING field/function in the rest of the list.
TODO
1) The current implementation can produce false comparison results for
expressions like:
date_time_field BETWEEN string_field_with_dates AND string_constant
if the string_constant will omit some of leading zeroes.
In order to fully implement correct comparison of DATE/TIME the new
DATETIME_RESULT result type should be introduced and agg_cmp_type()
should return the DATE/TIME field used for the conversion. Later
this field can be used by comparison functions like Item_func_between to
convert string values to ints on the fly and thus return correct results.
This modification will affect functions BETWEEN, IN and CASE.
2) If in the list a DATE field/function and a DATETIME field/function
are present in the list then the first found field/function will be
used for conversion. This may lead to wrong results and probably should
be fixed.
*/
static void agg_cmp_type(THD *thd, Item_result *type, Item **items, uint nitems)
{
uint i;
Item::Type res= (Item::Type)0;
/* Used only for date/time fields, max_length = 19 */
char buff[20];
uchar null_byte;
Field *field= NULL;
/* If the first argument is a FIELD_ITEM, pull out the field. */
if (items[0]->real_item()->type() == Item::FIELD_ITEM)
field=((Item_field *)(items[0]->real_item()))->field;
/* But if it can't be compared as a longlong, we don't really care. */
if (field && !field->can_be_compared_as_longlong())
field= NULL;
type[0]= items[0]->result_type();
for (i= 1; i < nitems; i++)
/* Search for date/time fields/functions */
for (i= 0; i < nitems; i++)
{
type[0]= item_cmp_type(type[0], items[i]->result_type());
if (field && convert_constant_item(thd, field, &items[i]))
type[0]= INT_RESULT;
if (!items[i]->result_as_longlong())
{
/* Do not convert anything if a string field/function is present */
if (!items[i]->const_item() && items[i]->result_type() == STRING_RESULT)
{
i= nitems;
break;
}
continue;
}
if ((res= items[i]->real_item()->type()) == Item::FIELD_ITEM)
{
field= ((Item_field *)items[i]->real_item())->field;
break;
}
else if (res == Item::FUNC_ITEM)
{
field= items[i]->tmp_table_field_from_field_type(0);
if (field)
field->move_field(buff, &null_byte, 0);
break;
}
}
if (field)
{
/* Check the rest of the list for presence of a string field/function. */
for (i++ ; i < nitems; i++)
{
if (!items[i]->const_item() && items[i]->result_type() == STRING_RESULT &&
!items[i]->result_as_longlong())
{
if (res == Item::FUNC_ITEM)
delete field;
field= 0;
break;
}
}
}
/* Reset to 0 on first occurence of non-const item. 1 otherwise */
bool is_const= items[0]->const_item();
/*
If the first item is a date/time function then its result should be
compared as int
*/
if (field)
{
/* Suppose we are comparing dates and some non-constant items are present. */
type[0]= INT_RESULT;
is_const= 0;
}
else
type[0]= items[0]->result_type();
for (i= 0; i < nitems ; i++)
{
if (!items[i]->const_item())
{
Item_result result= field && items[i]->result_as_longlong() ?
INT_RESULT : items[i]->result_type();
type[0]= is_const ? result : item_cmp_type(type[0], result);
is_const= 0;
}
else if (is_const)
type[0]= item_cmp_type(type[0], items[i]->result_type());
else if (field)
convert_constant_item(thd, field, &items[i]);
}
if (res == Item::FUNC_ITEM && field)
delete field;
}
@@ -238,14 +357,6 @@ static bool convert_constant_item(THD *thd, Field *field, Item **item)
if (!(*item)->with_subselect && (*item)->const_item())
{
/* For comparison purposes allow invalid dates like 2000-01-32 */
TABLE *table= field->table;
ulong orig_sql_mode= table->in_use->variables.sql_mode;
my_bitmap_map *old_write_map=
dbug_tmp_use_all_columns(table, table->write_set);
my_bitmap_map *old_read_map=
dbug_tmp_use_all_columns(table, table->read_set);
table->in_use->variables.sql_mode|= MODE_INVALID_DATES;
if (!(*item)->save_in_field(field, 1) && !((*item)->null_value))
{
Item *tmp= new Item_int_with_ref(field->val_int(), *item,
@@ -1106,9 +1217,8 @@ void Item_func_between::fix_length_and_dec()
return;
agg_cmp_type(thd, &cmp_type, args, 3);
if (cmp_type == STRING_RESULT &&
agg_arg_charsets(cmp_collation, args, 3, MY_COLL_CMP_CONV))
return;
if (cmp_type == STRING_RESULT)
agg_arg_charsets(cmp_collation, args, 3, MY_COLL_CMP_CONV);
}