When storing a large number to a FLOAT or DOUBLE field with fixed length, it could be incorrectly truncated if the field's length was greater than 31.
This patch also does some code cleanups to be able to reuse code which is common between Field_float::store() and Field_double::store().
is involved.
The Arg_comparator::compare_datetime() comparator caches its arguments if
they are constants i.e. const_item() returns true. The
Item_func_get_user_var::const_item() returns true or false based on
the current query_id and the query_id where the variable was created.
Thus even if a query can change its value its const_item() still will return
true. All this leads to a wrong comparison result when an object of the
Item_func_get_user_var class is involved.
Now the Arg_comparator::can_compare_as_dates() and the
get_datetime_value() functions never cache result of the GET_USER_VAR()
function (the Item_func_get_user_var class).
Made year 2000 handling more uniform
Removed year 2000 handling out from calc_days()
The above removes some bugs in date/datetimes with year between 0 and 200
Now we get a note when we insert a datetime value into a date column
For default values to CREATE, don't give errors for warning level NOTE
Fixed some compiler failures
Added library ws2_32 for windows compilation (needed if we want to compile with IOCP support)
Removed duplicate typedef TIME and replaced it with MYSQL_TIME
Better (more complete) fix for: Bug#21103 "DATE column not compared as DATE"
Fixed properly Bug#18997 "DATE_ADD and DATE_SUB perform year2K autoconversion magic on 4-digit year value"
Fixed Bug#23093 "Implicit conversion of 9912101 to date does not match cast(9912101 as date)"
function.
A wrong condition was used to check that the
Arg_comparator::can_compare_as_dates() function calculated the value of the
string constant. When comparing a non-const STRING function with a constant
DATETIME function it leads to saving an arbitrary value as a cached value of
the DATETIME function.
Now the Arg_comparator::set_cmp_func() function initializes the const_value
variable to the impossible DATETIME value (-1) and this const_value is
cached only if it was changed by the Arg_comparator::can_compare_as_dates()
function.
The IN function was comparing DATE/DATETIME values either as ints or as
strings. Both methods have their disadvantages and may lead to a wrong
result.
Now IN function checks whether all of its arguments has the STRING result
types and at least one of them is a DATE/DATETIME item. If so it uses either
an object of the in_datetime class or an object of the cmp_item_datetime
class to perform its work. If the IN() function arguments are rows then
row columns are checked whether the DATE/DATETIME comparator should be used
to compare them.
The in_datetime class is used to find occurence of the item to be checked
in the vector of the constant DATE/DATETIME values. The cmp_item_datetime
class is used to compare items one by one in the DATE/DATETIME context.
Both classes obtain values from items with help of the get_datetime_value()
function and cache the left item if it is a constant one.
The LEAST/GREATEST functions compared DATE/DATETIME values as
strings which in some cases could lead to a wrong result.
A new member function called cmp_datetimes() is added to the
Item_func_min_max class. It compares arguments in DATETIME context
and returns index of the least/greatest argument.
The Item_func_min_max::fix_length_and_dec() function now detects when
arguments should be compared in DATETIME context and sets the newly
added flag compare_as_dates. It indicates that the cmp_datetimes() function
should be called to get a correct result.
Item_func_min_max::val_xxx() methods are corrected to call the
cmp_datetimes() function when needed.
Objects of the Item_splocal class now stores and reports correct original
field type.
The BETWEEN function was comparing DATE/DATETIME values either as ints or as
strings. Both methods have their disadvantages and may lead to a wrong
result.
Now BETWEEN function checks whether all of its arguments has the STRING result
types and at least one of them is a DATE/DATETIME item. If so it sets up
two Arg_comparator obects to compare with the compare_datetime() comparator
and uses them to compare such items.
Added two Arg_comparator object members and one flag to the
Item_func_between class for the correct DATE/DATETIME comparison.
The Item_func_between::fix_length_and_dec() function now detects whether
it's used for DATE/DATETIME comparison and sets up newly added Arg_comparator
objects to do this.
The Item_func_between::val_int() now uses Arg_comparator objects to perform
correct DATE/DATETIME comparison.
The owner variable of the Arg_comparator class now can be set to NULL if the
caller wants to handle NULL values by itself.
Now the Item_date_add_interval::get_date() function ajusts cached_field type according to the detected type.
DATE and DATETIME can be compared either as strings or as int. Both
methods have their disadvantages. Strings can contain valid DATETIME value
but have insignificant zeros omitted thus became non-comparable with
other DATETIME strings. The comparison as int usually will require conversion
from the string representation and the automatic conversion in most cases is
carried out in a wrong way thus producing wrong comparison result. Another
problem occurs when one tries to compare DATE field with a DATETIME constant.
The constant is converted to DATE losing its precision i.e. losing time part.
This fix addresses the problems described above by adding a special
DATE/DATETIME comparator. The comparator correctly converts DATE/DATETIME
string values to int when it's necessary, adds zero time part (00:00:00)
to DATE values to compare them correctly to DATETIME values. Due to correct
conversion malformed DATETIME string values are correctly compared to other
DATE/DATETIME values.
As of this patch a DATE value equals to DATETIME value with zero time part.
For example '2001-01-01' equals to '2001-01-01 00:00:00'.
The compare_datetime() function is added to the Arg_comparator class.
It implements the correct comparator for DATE/DATETIME values.
Two supplementary functions called get_date_from_str() and get_datetime_value()
are added. The first one extracts DATE/DATETIME value from a string and the
second one retrieves the correct DATE/DATETIME value from an item.
The new Arg_comparator::can_compare_as_dates() function is added and used
to check whether two given items can be compared by the compare_datetime()
comparator.
Two caching variables were added to the Arg_comparator class to speedup the
DATE/DATETIME comparison.
One more store() method was added to the Item_cache_int class to cache int
values.
The new is_datetime() function was added to the Item class. It indicates
whether the item returns a DATE/DATETIME value.
are used as arguments of the IN predicate.
Added a function to check compatibility of row expressions. Made sure that this
function to be called for Item_func_in objects by fix_length_and_dec().
IN/BETWEEN predicates in sorting expressions.
Wrong results may occur when the select list contains an expression
with IN/BETWEEN predicate that differs from a sorting expression by
an additional NOT only.
Added the method Item_func_opt_neg::eq to compare correctly expressions
containing [NOT] IN/BETWEEN.
The eq method inherited from the Item_func returns TRUE when comparing
'a IN (1,2)' with 'a NOT IN (1,2)' that is not, of course, correct.
