The problem was that any VIEW columns had always implicit derivation.
Fix: derivation is now copied from the original expression
given in VIEW definition.
For example:
- a VIEW column which comes from a string constant
in CREATE VIEW definition have now coercible derivation.
- a VIEW column having COLLATE clause
in CREATE VIEW definition have now explicit derivation.
Problem: when embedding a character string with introducer with charset X
into a SQL query which is generally in character set Y, the string constants
were escaped according to their own character set (i.e.X), then after reading
such a "mixed" query from binlog, the string constants were unescaped
using character set of the query (i.e. Y), instead of X, which gave wrong
results or even syntax errors with tricky charsets (e.g. sjis)
Fix: when embedding a string constant of charset X into a query of charset Y,
the string constant is now escaped according to character Y, instead of
its own character set X.
on large length
Problem: Most (all) of the numeric inputs were being coerced into
int (32 bit) sized variables. Works OK for sane inputs; any input
larger than 2^32 (or 2^31 for signed vars) exihibited predictable
wrapping behavior (up to about 10^18) and then started having really
strange behaviour past that point (since the conversion to 64 bit int
from the DECIMAL type can do weird things on out of range numbers).
Solution: 1) Add many tests. 2) Convert input from (u)long type to
(u)longlong. 3) Do (sometimes multiple) sanity checks on input,
keeping in mind that sometimes a negative longlong is not a negative
longlong (if the unsigned_flag is set). 4) Emulate existing behavior
w/rt negative and "small" out-of-bounds values.
Problem: After introducing of LC_TIME_NAMES variable, the
function date_format() can return international non-ascii
characters in month and weekday names. Thus, it cannot return
a binary string anymore, because inserting a result of date_format()
into a column with non-utf8 character set produces garbage.
Fix: date_format() now returns a character string, using
"collation_connection" to detect character set and collation
for the returned value. This allows to insert
results of date_format() properly into columns with
various character sets.
- When returning metadata for scalar subqueries the actual type of the
column was calculated based on the value type, which limits the actual
type of a scalar subselect to the set of (currently) 3 basic types :
integer, double precision or string. This is the reason that columns
of types other then the basic ones (e.g. date/time) are reported as
being of the corresponding basic type.
Fixed by storing/returning information for the column type in addition
to the result type.
Problem: GROUP_CONCAT on a multi-byte column can truncate
in the middle of a multibyte character when applying
group_concat_max_len limit. It produces an invalid
multi-byte character in the result string.
The second, easier version - reusing old "warning_for_row" flag,
instead of introducing of "result_is_full" - which was
added in the previous commit.
The Item_func_mod objects never had maybe_null set, so users had no reason
to expect that they can be NULL, and may therefore deduce wrong results.
Now, set maybe_null.
