GitLab

Evaluate "NULL IN (SELECT ...)" in a special way: Disable pushed-down 
conditions and their "consequences": 
 = Do full table scans instead of unique_[index_subquery] lookups.
 = Change appropriate "ref_or_null" accesses to full table scans in
   subquery's joins.
Also cache value of NULL IN (SELECT ...) if the SELECT is not correlated 
wrt any upper select.


mysql-test/r/subselect.result:
  BUG#8804: wrong results for NULL IN (SELECT ...): 
   - Updated test results
sql/item.h:
  BUG#8804: wrong results for NULL IN (SELECT ...): 
   - Added comments
sql/item_cmpfunc.cc:
  BUG#8804: wrong results for NULL IN (SELECT ...): 
  Made Item_in_optimizer to:
  - cache the value of "NULL IN (uncorrelated select)"
  - Turn off pushed-down predicates when evaluating "NULL IN (SELECT ...)"
sql/item_cmpfunc.h:
  BUG#8804: wrong results for NULL IN (SELECT ...): 
  - Made Item_in_optimizer cache the value of "NULL IN (uncorrelated select)"
  - Added comments
sql/item_subselect.cc:
  BUG#8804: wrong results for NULL IN (SELECT ...):
  - When needed, wrap the predicates we push into subquery into an 
    Item_func_trig_cond so we're able to turn them off when evaluating 
    NULL IN (SELECT ...).
  - Added code to evaluate NULL IN (SELECT ...) in a special way:
    = In [unique_]index_subquery, do full table scan to see if there 
      are any rows.
    = For other subqueries, change ref[_or_null] to ALL if the
      ref[_or_null] was created from pushed-down predicate.
sql/item_subselect.h:
  BUG#8804: wrong results for NULL IN (SELECT ...):
  - Added Item_subselect::is_correlated
  - Added comments
sql/records.cc:
  BUG#8804: wrong results for NULL IN (SELECT ...):
  - Make rr_sequential() non-static
sql/sql_lex.cc:
  BUG#8804: wrong results for NULL IN (SELECT ...):
  - Added st_select_lex::is_correlated and Item_subselect::is_correlated.
sql/sql_lex.h:
  BUG#8804: wrong results for NULL IN (SELECT ...):
  - Added st_select_lex::is_correlated
sql/sql_select.cc:
  BUG#8804: wrong results for NULL IN (SELECT ...):
  - Added KEY_FIELD::outer_ref to keep track of which ref accesses are 
    created from predicates that were pushed down into the subquery.
sql/sql_select.h:
  BUG#8804: wrong results for NULL IN (SELECT ...):
  - Added KEYUSE::outer_ref
mysql-test/r/subselect3.result:
  New BitKeeper file ``mysql-test/r/subselect3.result''
mysql-test/t/subselect3.test:
  New BitKeeper file ``mysql-test/t/subselect3.test''

account predicates that become sargable after reading const tables.
In some cases this resulted in choosing non-optimal execution plans.
Now info of such potentially saragable predicates is saved in
an array and after reading const tables we check whether this
predicates has become saragable.



mysql-test/r/select.result:
  Added a test case for bug #19579.
mysql-test/t/select.test:
  Added a test case for bug #19579.
sql/item_cmpfunc.cc:
  Fixed bug #19579: at range analysis optimizer did not take into 
  account predicates that become sargable after reading const tables.
  Added a counter of between predicates.
sql/sql_base.cc:
  Fixed bug #19579: at range analysis optimizer did not take into 
  account predicates that become sargable after reading const tables.
  Added a counter of between predicates.
sql/sql_lex.cc:
  Fixed bug #19579: at range analysis optimizer did not take into 
  account predicates that become sargable after reading const tables.
  Added a counter of between predicates.
sql/sql_lex.h:
  Fixed bug #19579: at range analysis optimizer did not take into 
  account predicates that become sargable after reading const tables.
  Added a counter of between predicates.
sql/sql_select.cc:
  Fixed bug #19579: at range analysis optimizer did not take into 
  account predicates that become sargable after reading const tables.
  Now info of such potentially saragable predicates is saved in
  an array and after reading const tables we check whether this
  predicates has become saragable.

  Added the test case for bug#21677: Wrong result when comparing a DATE and a DATETIME in BETWEEN
  Corrected a test case after removal of fix for bug#16377
query_cache.result, func_time.test, view.result, view.test, func_time.result:
  Corrected a test case after removal of fix for bug#16377
type_date.test:
  Added the test case for bug#21677: Wrong result when comparing a DATE and a DATETIME in BETWEEN
   Corrected a test case after removal of fix for bug#16377
item_cmpfunc.cc:
  Removed changes to the Item_func_between::fix_length_and_dec() made in the fix for bug#16377


mysql-test/t/view.test:
  Corrected a test case after removal of fix for bug#16377
mysql-test/t/type_date.test:
  Added the test case for bug#21677: Wrong result when comparing a DATE and a DATETIME in BETWEEN
   Corrected a test case after removal of fix for bug#16377
mysql-test/t/func_time.test:
  Corrected a test case after removal of fix for bug#16377
mysql-test/r/view.result:
  Corrected a test case after removal of fix for bug#16377
mysql-test/r/type_date.result:
  Added the test case for bug#21677: Wrong result when comparing a DATE and a DATETIME in BETWEEN
  Corrected a test case after removal of fix for bug#16377
mysql-test/r/query_cache.result:
  Corrected a test case after removal of fix for bug#16377
mysql-test/r/func_time.result:
  Corrected a test case after removal of fix for bug#16377
sql/item_cmpfunc.cc:
  Removed changes to the Item_func_between::fix_length_and_dec() made in the fix for bug#16377

Cset exclude: kaa@polly.local|ChangeSet|20060908100829|09983


sql/item_cmpfunc.cc:
  Exclude
sql/item_cmpfunc.h:
  Exclude
sql/item_func.cc:
  Exclude
sql/item_func.h:
  Exclude
sql/log_event.cc:
  Exclude
sql/sql_class.h:
  Exclude
mysql-test/r/case.result:
  Exclude
mysql-test/r/func_if.result:
  Exclude
mysql-test/r/func_test.result:
  Exclude
mysql-test/r/user_var.result:
  Exclude
mysql-test/t/case.test:
  Exclude
mysql-test/t/func_if.test:
  Exclude
mysql-test/t/func_test.test:
  Exclude
mysql-test/t/user_var.test:
  Exclude

  Removed changes to the Item_func_between::fix_length_and_dec() made in the fix for bug#16377
query_cache.result:
  Corrected a test case after removing a fix for bug#16377


mysql-test/r/query_cache.result:
  Corrected a test case after removing a fix for bug#16377
sql/item_cmpfunc.cc:
  Removed changes to the Item_func_between::fix_length_and_dec() made in the fix for bug#16377

- Honor unsigned_flag in the corresponding functions
- Use compare_int_signed_unsigned()/compare_int_unsigned_signed() instead of explicit comparison in GREATEST() and LEAST()


mysql-test/r/case.result:
  Added test case for bug #20924
mysql-test/r/func_if.result:
  Added test case for bug #20924
mysql-test/r/func_test.result:
  Added test case for bug #20924
mysql-test/r/user_var.result:
  Added test case for bug #20924
mysql-test/t/case.test:
  Added test case for bug #20924
mysql-test/t/func_if.test:
  Added test case for bug #20924
mysql-test/t/func_test.test:
  Added test case for bug #20924
mysql-test/t/user_var.test:
  Added test case for bug #20924
sql/item_cmpfunc.cc:
  Bug #20924: CAST(expr as UNSIGNED) returns SIGNED value when used in various functions
  
  - Moved some code out of Arg_comparator to external functions to be reused in Item_func_min_max
  - Fixed IFNULL(), IF(), CASE() and COALESCE()
sql/item_cmpfunc.h:
  Bug #20924: CAST(expr as UNSIGNED) returns SIGNED value when used in various functions
  
  - Moved some code out of Arg_comparator to external functions to be reused in Item_func_min_max
sql/item_func.cc:
  Bug #20924: CAST(expr as UNSIGNED) returns SIGNED value when used in various functions
  
  Fixed LEAST(), GREATEST() and "SET @A=..." parts
sql/item_func.h:
  Bug #20924: CAST(expr as UNSIGNED) returns SIGNED value when used in various functions
  
  Fixed "SET @A=..." part
sql/sql_class.h:
  Bug #20924: CAST(expr as UNSIGNED) returns SIGNED value when used in various functions
  
  Fixed "SET @A=..." part

  Corrected test case after removal of fix for bug#16377         
type_date.test:
  Corrected test case after removal of fix for bug#16377
item_cmpfunc.cc:
  Removed changes to the agg_cmp_type() made in the for bug#16377


mysql-test/t/type_date.test:
  Corrected test case after removal of fix for bug#16377
mysql-test/t/func_time.test:
  Corrected test case after removal of fix for bug#16377
mysql-test/r/type_date.result:
  Corrected test case after removal of fix for bug#16377
mysql-test/r/query_cache.result:
  Corrected test case after removal of fix for bug#16377
mysql-test/r/func_time.result:
  Corrected test case after removal of fix for bug#16377
sql/item_cmpfunc.cc:
  Removed changes to the agg_cmp_type() made in the for bug#16377

equal constant under any circumstances.
In fact this substitution can be allowed if the field is
not of a type string or if the field reference serves as 
an argument of a comparison predicate.  


mysql-test/r/func_str.result:
  Added test cases for bug #21698.
mysql-test/r/heap_hash.result:
  Adjusted results after the fix for bug #21198.
mysql-test/t/func_str.test:
  Added test cases for bug #21698.
sql/item.cc:
  Fixed bug #21198.
  Added a method to check whether a field reference can be 
  substituted for a constant equal to the field.
  This substitution is allowed if the field is not of a type string
  or if the field reference serves as an argument of a comparison
  predicate.
sql/item.h:
  Fixed bug #21698.
  Added a new virtual transformation method for a item 'compile'
  with two callback function parameters.
  Added a new virtual method 'subst_argument_checker' to be used
  as an amnalyzer method.
  This method is supposed to set it...

Changes in an item tree done by optimizer weren't properly
registered and went unnoticed, which resulted in preliminary freeing
of used memory.


mysql-test/r/ps.result:
  Add result for bug#21166: Prepared statement causes signal 11
  on second execution.
mysql-test/t/ps.test:
  Add test case for bug#21166: Prepared statement causes signal 11
  on second execution.
sql/item.cc:
  Move Item::transform() and Item_default_value::transform() from
  item.h here and use THD::change_item_tree() instead of plain
  assignment.
  Change Item_field::set_no_const_sub() to be used with Item::walk()
  instead of Item::transform().
sql/item.h:
  Move definition of Item::transform() and Item_default_value::transform()
  to item.cc.
  Change Item::set_no_const_sub() to be used with Item::walk()
  instead of Item::transform().
sql/item_cmpfunc.cc:
  Use Item::walk() to execute Item::set_no_const_sub().
  Use THD::change_item_tree() instead of plain assignment.
sql/item_func.cc:
  Add assert and comment to Item_func::traverse_cond().
sql/item_row.cc:
  Use THD::change_item_tree() instead of plain assignment.
sql/item_strfunc.cc:
  Move Item_func_make_set::transform() from item_strfunc.h here and use
  THD::change_item_tree() instead of plain assignment.
sql/item_strfunc.h:
  Move definition of Item_func_make_set::transform() to item_strfunc.cc.

  Additional fix for bug #21475
item_func.h, item_func.cc:
  Additional fix for bug#16861


sql/item_func.h:
  Additional fix for bug#16861
sql/item_func.cc:
  Additional fix for bug#16861
sql/item_cmpfunc.cc:
  Additional fix for bug #21475
sql/item.cc:
  Additional fix for bug #21475

A date can be represented as an int (like 20060101) and as a string (like
"2006.01.01"). When a DATE/TIME field is compared in one SELECT against both
representations the constant propagation mechanism leads to comparison
of DATE as a string and DATE as an int. In this example it compares 2006 and
20060101 integers. Obviously it fails comparison although they represents the
same date.


Now the Item_bool_func2::fix_length_and_dec() function sets the comparison
context for items being compared. I.e. if items compared as strings the
comparison context is STRING.
The constant propagation mechanism now doesn't mix items used in different
comparison contexts. The context check is done in the
Item_field::equal_fields_propagator() and in the change_cond_ref_to_const() 
functions.

Also the better fix for bug 21159 is introduced.


mysql-test/t/type_datetime.test:
  Added a test case for bug#21475: Wrongly applied constant propagation leads to a false comparison.
mysql-test/r/type_datetime.result:
  Added a test case for bug#21475: Wrongly applied constant propagation leads to a false comparison.
sql/sql_select.cc:
  Fixed bug#21475: Wrongly applied constant propagation leads to a false comparison.
  The constant propagation mechanism now doesn't mix items used in different
  comparison contexts. The check is done in the change_cond_ref_to_const() function.
sql/item_cmpfunc.cc:
  Fixed bug#21475: Wrongly applied constant propagation leads to a false comparison.
  Now the Item_bool_func2::fix_length_and_dec() function sets the comparison
  context for items being compared.
sql/item.h:
  Fixed bug#21475: Wrongly applied constant propagation leads to a false comparison.
  To the Item class a new field called cmp_context is added.
  It represents the comparison context of an item.
sql/item.cc:
  Fixed bug#21475: Wrongly applied constant propagation leads to a false comparison.
  The constant propagation mechanism now doesn't mix items used in different
  comparison contexts. The context check is done in the
  Item_field::equal_fields_propagator() function.

This bug is a side-effect of bug fix #16377. NOW() is optimized in
BETWEEN to integer constants to speed up query execution. When view is being
created it saves already modified query and thus becomes wrong.

The agg_cmp_type() function now substitutes constant result DATE/TIME functions 
for their results only if the current query isn't CREATE VIEW or SHOW CREATE
VIEW.


mysql-test/t/view.test:
  Added a test case for bug#15950: NOW() optimized away in VIEWs
mysql-test/r/view.result:
  Added a test case for bug#15950: NOW() optimized away in VIEWs
sql/item_cmpfunc.cc:
  Fixed bug#15950: NOW() optimized away in VIEWs
  The agg_cmp_type() function now substitutes constant result DATE/TIME functions 
  for their results only if the current query isn't CREATE VIEW or SHOW CREATE
  VIEW.

  Add implementations of Item_func_{nop,not}_all::neg_transformer


mysql-test/r/subselect.result:
  BUG#20975: testcase
mysql-test/t/subselect.test:
  BUG#20975: testcase
sql/mysql_priv.h:
  Make chooser_compare_func_creator visible in item.h

  
Two functions have different ideas of what a string should look like;
one of them reads memory it assumes the other one may have written.
And "if you assume ..."
  
We now use a more defensive variety of the assuming function, this fixes
a warning thrown by the valgrind tool.


sql/item_cmpfunc.cc:
  c_ptr() makes incorrect assumptions about the string we get from
  out of args[0]->val_str(&tmp); c_str_safe() is more defensive.

In some functions dealing with strings and character sets, the wrong
pointers were saved for restoration in THD::rollback_item_tree_changes().
This could potentially cause random corruption or crashes.

Fixed by passing the original Item ** locations, not local stack copies.

Also remove unnecessary use of default arguments.


sql/item.cc:
  Function agg_item_charsets() now handles non-consequtive Item *'s.
sql/item.h:
  Remove use of default argument.
sql/item_cmpfunc.cc:
  Remove use of default argument.
sql/item_func.cc:
  Remove use of default argument.
sql/item_func.h:
  Function agg_item_charsets() now handles non-consequtive Item *'s.
sql/item_strfunc.cc:
  Pass original Item **'s to agg_arg_charsets(), not local copies, to ensure
  proper restoration in THD::rollback_item_tree_changes().
sql/item_sum.cc:
  Remove use of default argument.

  Added test case for bug#18759 Incorrect string to numeric conversion.  
select.test:
  Added test case for bug#18759 Incorrect string to numeric conversion.
item_cmpfunc.cc:
  Cleanup after fix for bug#18360 removal


sql/item_cmpfunc.cc:
  Cleanup after fix for bug#18360 removal
mysql-test/t/select.test:
  Added test case for bug#18759 Incorrect string to numeric conversion.
mysql-test/r/select.result:
  Added test case for bug#18759 Incorrect string to numeric conversion.

  After merge fix


sql/item_cmpfunc.cc:
  After merge fix

  Reverted fix for bug#18360


mysql-test/t/func_in.test:
  Reverted fix for bug#18360
mysql-test/r/func_in.result:
  Reverted fix for bug#18360
sql/item_cmpfunc.cc:
  Reverted fix for bug#18360

  Fix for bug#16716 for --ps-protocol mode.
item_cmpfunc.cc:
  Fix for a memory allocation/freeing problem in agg_cmp_type() after fix
for bug#16377. Few language corrections.


sql/item_cmpfunc.cc:
  Fix for a memory allocation/freeing problem in agg_cmp_type(). Few language corrections.
sql/item_strfunc.cc:
  Fix for bug#16716 for --ps-protocol mode.

  After merge fix


mysql-test/r/func_time.result:
  After merge fix
mysql-test/r/func_concat.result:
  After merge fix
mysql-test/r/cast.result:
  After merge fix
sql/item_cmpfunc.h:
  After merge fix
sql/item_cmpfunc.cc:
  After merge fix
sql/field.cc:
  After merge fix

can lead to a wrong result.

All date/time functions has the STRING result type thus their results are
compared as strings. The string date representation allows a user to skip 
some of leading zeros. This can lead to wrong comparison result if a date/time 
function result is compared to such a string constant.

The idea behind this bug fix is to compare results of date/time functions
and data/time constants as ints, because that date/time representation is 
more exact. To achieve this the agg_cmp_type() is changed to take in the
account that a date/time field or an date/time item should be compared 
as ints.

This bug fix is partially back ported from 5.0.

The agg_cmp_type() function now accepts THD as one of parameters. 
In addition, it now checks if a date/time field/function is present in the
list. If so, it tries to coerce all constants to INT to make date/time
comparison return correct result. The field for the constant coercion is
taken from the Item_field or constructed from the Item_func. In latter case
the constructed field will be freed after conversion of all constant items.
Otherwise the result is same as before - aggregated with help of the
item_cmp_type() function.

From the Item_func_between::fix_length_and_dec() function removed the part
which was converting date/time constants to int if possible. Now this is 
done by the agg_cmp_type() function.

The new function result_as_longlong() is added to the Item class. 
It indicates that the item is a date/time item and result of it can be
compared as int. Such items are date/time fields/functions.

Correct val_int() methods are implemented for classes Item_date_typecast, 
Item_func_makedate, Item_time_typecast, Item_datetime_typecast. All these
classes are derived from Item_str_func and Item_str_func::val_int() converts
its string value to int without regard to the date/time type of these items.

Arg_comparator::set_compare_func() and Arg_comparator::set_cmp_func()
functions are changed to substitute result type of an item with the INT_RESULT
if the item is a date/time item and another item is a constant. This is done
to get a correct result of comparisons like date_time_function() = string_constant.


mysql-test/r/cast.result:
  Fixed wrong test case result after bug fix#16377.
sql/item_timefunc.h:
  Fixed bug#16377: result of DATE/TIME functions were compared as strings which
  can lead to a wrong result.
  The result_as_longlong() function is set to return TRUE for these classes:
  Item_date, Item_date_func, Item_func_curtime, Item_func_sec_to_time,
  Item_date_typecast, Item_time_typecast, Item_datetime_typecast,
  Item_func_makedate.
sql/item_timefunc.cc:
  Fixed bug#16377: result of DATE/TIME functions were compared as strings which
  can lead to a wrong result.Correct val_int() methods are implemented for classes Item_date_typecast, 
  Item_func_makedate, Item_time_typecast, Item_datetime_typecast.
sql/item_cmpfunc.h:
  Fixed bug#16377: result of DATE/TIME functions were compared as strings which
  can lead to a wrong result.
  Arg_comparator::set_compare_func() and Arg_comparator::set_cmp_func()
  functions are changed to substitute result type of an item with the INT_RESULT
  if the item is a date/time item and another item is a constant.
sql/field.cc:
  Fixed bug#16377: result of DATE/TIME functions were compared as strings which
  can lead to a wrong result.
  Field::set_warning(), Field::set_datetime_warning() now use current_thd to get thd if table isn't set.
sql/item_cmpfunc.cc:
  Fixed bug#16377: result of DATE/TIME functions were compared as strings which
  can lead to a wrong result.
  The agg_cmp_type() function now accepts THD as one of parameters. 
  In addition, it now checks if a date/time field/function is present in the
  list. If so, it tries to coerce all constants to INT to make date/time
  comparison return correct result. The field for the constant coercion is
  taken from the Item_field or constructed from the Item_func. In latter case
  the constructed field will be freed after conversion of all constant items.
  Otherwise the result is same as before - aggregated with help of the
  item_cmp_type() function.
sql/item.h:
  The new function result_as_longlong() is added to the Item class. 
  It indicates that the item is a date/time item and result of it can be
  compared as int. Such items are date/time fields/functions.
mysql-test/t/func_time.test:
  Added test case fot bug#16377: result of DATE/TIME functions were compared as strings which
  can lead to a wrong result.
mysql-test/r/func_time.result:
  Added test case fot bug#16377: result of DATE/TIME functions were compared as strings which
  can lead to a wrong result.

  After merge fix


mysql-test/r/multi_update.result:
  After merge fix
mysql-test/r/func_in.result:
  After merge fix
sql/item_cmpfunc.cc:
  After merge fix

The IN() function uses agg_cmp_type() to aggregate all types of its arguments
to find out some common type for comparisons. In this particular case the 
char() and the int was aggregated to double because char() can contain values
like '1.5'. But all strings which do not start from a digit are converted to
0. thus 'a' and 'z' become equal. 
This behaviour is reasonable when all function arguments are constants. But 
when there is a field or an expression this can lead to false comparisons. In
this case it makes more sense to coerce constants to the type of the field
argument.

The agg_cmp_type() function now aggregates types of constant and non-constant
items separately. If some non-constant items will be found then their
aggregated type will be returned. Thus after the aggregation constants will be
coerced to the aggregated type. 


mysql-test/t/func_in.test:
  Added test case for bug#18360: Incorrect type coercion in IN() results in false comparison.
mysql-test/r/func_in.result:
  Added test case for bug#18360: Incorrect type coercion in IN() results in false comparison.
sql/item_cmpfunc.cc:
  Fixed bug#18360: Incorrect type coercion in IN() results in false comparison.
  The agg_cmp_type() function now aggregates types of constant and non-constant
  items separately. If some non-constant items will be found then their
  aggregated type will be returned. Thus after the aggregation constants will
  be coerced to the aggregated type.

This bug was introduced when the patch resolving the
performance problem 17164 was applied. As a result
of that modification the not_null_tables attributes
were calculated incorrectly for constant OR conditions.
This triggered invalid conversion of outer joins into
inner joins.


mysql-test/r/join_outer.result:
  Added a test case for bug #19816.
mysql-test/t/join_outer.test:
  Added a test case for bug #19816.

The convert_constant_item() function converts constant items to ints on
prepare phase to optimize execution speed. In this case it tries to evaluate
subselect which contains a derived table and is contained in a derived table. 
All derived tables are filled only after all derived tables are prepared.
So evaluation of subselect with derived table at the prepare phase will
return a wrong result.

A new flag with_subselect is added to the Item class. It indicates that
expression which this item represents is a subselect or contains a subselect.
It is set to 0 by default. It is set to 1 in the Item_subselect constructor
for subselects.
For Item_func and Item_cond derived classes it is set after fixing any argument
in Item_func::fix_fields() and Item_cond::fix_fields accordingly.
The convert_constant_item() function now doesn't convert a constant item
if the with_subselect flag set in it. 


mysql-test/t/view.test:
  Added test case for bug#19077: A nested materialized derived table is used before being populated.
mysql-test/t/subselect.test:
  Added test case for bug#19077: A nested materialized derived table is used before being populated.
mysql-test/r/view.result:
  Added test case for bug#19077: A nested materialized derived table is used before being populated.
mysql-test/r/subselect.result:
  Added test case for bug#19077: A nested materialized derived table is used before being populated.
sql/item_subselect.cc:
  Fixed bug#19077: A nested materialized derived table is used before being populated.
  The Item_subselect class constructor sets new with_subselect flag to 1.
sql/item_func.cc:
  Fixed bug#19077: A nested materialized derived table is used before being populated.
  
  The Item_func::fix_fields() sets new with_subselect flag from with_subselect flags of its arguments.
sql/item_cmpfunc.cc:
  Fixed bug#19077: A nested materialized derived table is used before being populated.
  The convert_constant_item() function now doesn't convert a constant item
  with the with_subselect flag set.
  The Item_cond::fix_fields() sets new with_subselect flag from with_subselect flags of its arguments.
sql/item.cc:
  Fixed bug#19077: A nested materialized derived table is used before being populated.
  Set new with_subselect flag to default value - 0 in the Item constructor.
sql/item.h:
  Fixed bug#19077: A nested materialized derived table is used before being populated.
  A new flag with_subselect is added to the Item class. It indicates that
  expression which this item represents is a subselect or contains a subselect.
  It is set to 0 by default.

- after review fixes


sql/item_cmpfunc.cc:
  Bug #17896: MIN of CASE WHEN returns non-minimum value!
  - after review fixes.

If the second or the third argument of a BETWEEN predicate was
a constant expression, like '2005.09.01' - INTERVAL 6 MONTH,
while the other two arguments were fields then the predicate 
was evaluated incorrectly and the query returned a wrong
result set.
The bug was introduced in 5.0.17 when in the fix for 12612.


mysql-test/r/func_time.result:
  Added a test case for bug #18618.
mysql-test/t/func_time.test:
  Added a test case for bug #18618.

The function agg_cmp_type in item_cmpfunc.cc neglected the fact that 
the first argument in a BETWEEN/IN predicate could be a field of a view.
As a result in the case when the retrieved table was hidden by a view 
over it and the arguments in the BETWEEN/IN predicates are of 
the date/time type the function did not perform conversion of 
the constant arguments to the same format as the first field argument.
If formats of the arguments differed it caused wrong a evaluation of
the predicates.


mysql-test/r/view.result:
  Added a test case for bug #16069.
mysql-test/t/view.test:
  Added a test case for bug #16069.

Multiple equalities were not adjusted after reading constant tables.
It resulted in neglecting good index based methods that could be
used to access of other tables.


mysql-test/r/having.result:
  Adjusted a test case results after fix for bug #16504.
mysql-test/r/select.result:
  Added a test case for bug #16504.
mysql-test/r/subselect.result:
  Adjusted a test case results after fix for bug #16504.
mysql-test/r/varbinary.result:
  Adjusted a test case results after fix for bug #16504.
mysql-test/t/select.test:
  Added a test case for bug #16504.
sql/item.cc:
  Fixed bug #16504.
  An Item_equal object may contain only a constant member.
  It may happen after reading constant tables.
sql/item_cmpfunc.cc:
  Fixed bug #16504.
  Added method Item_equal::check_const that check appearance of new 
  constant items in a multiple equality.
sql/item_cmpfunc.h:
  Fixed bug #16504.
  Added method Item_equal::check_const that check appearance of new 
  constant items in a multiple equality.
sql/sql_select.cc:
  Fixed bug #16504.
  Adjusted multiple equalities after reading constant tables.
  Fixed a few typo in comments.

If the WHERE condition of a query contained an ORed FALSE term
then the set of tables whose rows cannot serve for null complements
in outer joins was determined incorrectly. It resulted in blocking 
possible conversions of outer joins into joins for such queries.


mysql-test/r/join_outer.result:
  Added a test case for bug #17164.
mysql-test/t/join_outer.test:
  Added a test case for bug #17164.

sql/item_cmpfunc.cc:
  Fix for bug #17896: MIN of CASE WHEN returns non-minimum value!
  - NULL items should not affect the result type.

When the Item_cond::fix_fields() function reduces cond tree, it in loop
scans it's own list and when it founds Item_cond with same function (AND
or OR) it does next things: 1) replaces that item with item's list. 2)
empties item's list. Due to this operation is done twice - for update and
for view, at the update phase cond's list of lower view is already empty.
Empty list returns ref to itself, thus making endless loop by replacing
list with itself, emptying, replacing again and so on. This results in
server hung up.

To the Item_cond::fix_fields() function added check that ensures that
list being replaced with isn't empty.


mysql-test/t/view.test:
  Added test for bug#17726: Not checked empty list caused endless loop
mysql-test/r/view.result:
  Added test for bug#17726: Not checked empty list caused endless loop
sql/item_cmpfunc.cc:
  Fixed bug#17726: Not checked empty list caused endless loop
  To the Item_cond::fix_fields() function added check that ensures that
  list being replaced with isn't empty.

 removed unnecessary calculation of cache value 
 otherwise Join::preapre tries to calculate 
 undefined values(filed values)


mysql-test/r/type_decimal.result:
  Fix for bug#17826 'type_decimal' fails with ps-protocol
   test case, this test case reproduce the same bug but without PS protocol
mysql-test/t/type_decimal.test:
  Fix for bug#17826 'type_decimal' fails with ps-protocol
   test case, this test case reproduce the same bug but without PS protocol

mysql-test/r/bigint.result:
  test result
mysql-test/t/bigint.test:
  testcase
sql/item.h:
  unsigned_arg is a separate parameter now
sql/item_cmpfunc.cc:
  we can get unsigned field from the signed Item - from string
  like '1234'

The Item_func_if::fix_length_and_dec() function when calculating length of 
result doesn't take into account unsigned_flag. But it is taken when 
calculating length of temporary field. This result in creating field that 
shorter than needed. Due to this, in the reported query 40.0 converted to 9.99.

The function Item_func_if::fix_length_and_dec() now adds 1 to the max_length if 
the unsigned_flag isn't set.


sql/item_cmpfunc.cc:
  Fixed bug#16272: IF function with decimal args can produce wrong result
  The function Item_func_if::fix_length_and_dec() now adds 1 to the max_length if 
  the unsigned_flag isn't set.
mysql-test/r/func_if.result:
  Added test case for bug#16272: IF function with decimal args can produce wrong result
mysql-test/t/func_if.test:
  Added test case for bug#16272: IF function with decimal args can produce wrong result

return incorrect result set for a select SQL request"


mysql-test/r/ps.result:
  Test results fixed (Bug#12734)
mysql-test/t/ps.test:
  A test case for Bug#12734
sql/item_cmpfunc.cc:
  Reset canDoTurboBM in Item_func_like::cleanup()
sql/item_cmpfunc.h:
  Add Item_func_like::cleanup()

select result

Item equal objects are employed only at the optimize phase. Usually they are not
supposed to be evaluated.  Yet in some cases we call the method val_int() for
them. Here we have to take care of restricting the predicate such an object
represents f1=f2= ...=fn to the projection of known fields fi1=...=fik.

Added a check for field's table being const in Item_equal::val_int().
If the field's table is not const val_int() just skips that field when
evaluating Item_equal.


mysql-test/t/select.test:
  Added test case for bug #15633: Evaluation of Item_equal for non-const table caused wrong select result
mysql-test/r/select.result:
  Added test case for bug #15633: Evaluation of Item_equal for non-const table caused wrong select result
mysql-test/r/func_group.result:
  Corrected test result for bug #12882 after fix for bug#15633
sql/item_cmpfunc.h:
  Fixed bug #15633: Evaluation of Item_equal for non-const table caused wrong select result
  Added comment about fields from non-const tables in class description.
sql/item_cmpfunc.cc:
  Fixed bug #15633: Evaluation of Item_equal for non-const table caused wrong select result
  Added check for field's table being const in Item_equal::val_int().