Fix when __attribute__() is stubbed out, add ATTRIBUTE_FORMAT() for specifying
__attribute__((format(...))) safely, make more use of the format attribute,
and fix some of the warnings that this turns up (plus a bonus unrelated one).
time_format() claimed %H and %k would return at most two digits
(hours 0-23), but this coincided neither with actual behaviour
nor with docs. this is not visible in simple queries; forcing
a temp-table is probably the easiest way to see this. adjusted
the return-length appropriately; the alternative would be to
adjust the docs to say that behaviour for > 99 hours is undefined.
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Bug#19844: time_format in Union truncates values
time_format() claimed %H and %k would return at most two digits
(hours 0-23), but this coincided neither with actual behaviour
nor with docs. this is not visible in simple queries; forcing
a temp-table is probably the easiest way to see this. adjusted
the return-length appropriately; the alternative would be to
adjust the docs to say that behaviour for > 99 hours is undefined.
str_to_date() would sometimes render NULL if %D was used as rule other than last.
since this was due to two pointers getting mixed up in the server, this behaviour
seemed somewhat non-deterministic at SQL level.
difference between timestamp in values of months and quarters.)
Problem: when requesting timestamp diff in months or quarters, it
would only examine the date (and not the time) for the comparison.
Solution: increased precision of comparison.
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.
itself when executing queries referring to a view with GROUP BY
an expression containing non-constant interval.
It happened because Item_date_add_interval::eq neglected the
fact that the method can be applied to an expression of the form
date(col) + interval time_to_sec(col) second
at the time when col could not be evaluated yet.
An attempt to evaluate time_to_sec(col) in this method resulted
in a crash.
Conversion from int and real numbers to UCS2 didn't work fine:
CONVERT(100, CHAR(50) UNICODE)
CONVERT(103.9, CHAR(50) UNICODE)
The problem appeared because numbers have binary charset, so,
simple charset recast binary->ucs2 was performed
instead of real conversion.
Fixed to make numbers pretend to be non-binary.
time per connection
Removed const_string() method from Item_string (it was only used in one
place, in a bad way). Defer possible SP variable, and access data directly
instead, in date_format item.
fix for bug #15828 after review
doing val_str now before testing of null value secures the function for null values returned by dynamic functions - the fix before was incomplete andy covered constant null values
Bad examples of usage of a string with its length fixed.
The incorrect length in the trigger file configuration descriptor
fixed (BUG#14090).
A hook for unknown keys added to the parser to support old .TRG files.
Removed wrong fix for bug #14009 (use of abs() on null value causes problems with filesort)
Mark that add_time(), time_diff() and str_to_date() can return null values
collation
By default constant strings in second parameter of date_time() have case
insensitive collation. Because of this expressions date_format(f,'%m') and
date_format(f,'%M') wrongly becomes equal, which results in choosing wrong
column to sort by.
Now if second parameter of date_format() is constant then it's collation is
changed to case sensitive.
