with COALESCE and JOIN
The server returned to a client the VARBINARY column type
instead of the DATE type for a result of the COALESCE,
IFNULL, IF, CASE, GREATEST or LEAST functions if that result
was filesorted in an anonymous temporary table during
the query execution.
For example:
SELECT COALESCE(t1.date1, t2.date2) AS result
FROM t1 JOIN t2 ON t1.id = t2.id ORDER BY result;
To create a column of various date/time types in a
temporary table the create_tmp_field_from_item() function
uses the Item::tmp_table_field_from_field_type() method
call. However, fields of the MYSQL_TYPE_NEWDATE type were
missed there, and the VARBINARY columns were created
by default.
Necessary condition has been added.
Send_field.org_col_name has broken value on secondary execution.
It happens when result field is created from the field which belongs to view
due to forgotten assignment of some Send_field attributes.
The fix:
set Send_field.org_col_name,org_table_name with correct value during Send_field intialization.
For a join query with GROUP BY and/or ORDER BY and a view reference
in the FROM list the metadata erroneously showed empty table aliases
and database names for the view columns.
Integer values with 10 digits may or may not fit into an int column
(e.g. 2147483647 vs 6147483647).
Thus when creating a temp table column for such an int we must
use bigint instead.
Fixed to use bigint.
Also subsituted a "magic number" with a named constant.
When compiling GROUP BY Item_ref instances are dereferenced in
setup_copy_fields(), i.e. replaced with the corresponding Item_field
(if they point to one) or Item_copy_string for the other cases.
Since the Item_ref (in the Item_field case) is no longer used the information
about the aliases stored in it is lost.
Fixed by preserving the column, table and DB alias on dereferencing Item_ref
procedure variable
Second version, after review.
Keep the unsigned_flag in Item_decimal updated. Note that this also changed
the result of several old test results - creating tables from decimal
templates now gives unsigned columns and different sizes. (Several tests
had Length > Max_length before.)
not default_charset_into. It fixes the
problem that in some cases numbers where
treated as CHAR(N), not as BINARY(N), e.g.
wrong 'charsetnr' when sent to the client side.
2. IFNULL didn't aggregate argument charsets
and collations, so IFNULL(1,'a') produced
a CHAR(N). Now produces a BINARY(N).
3. SELECT PROCEDURE ANALIZE now returns
BINARY columns, which is much better than it worked
previously: CHAR with the default character set.
But in the future it's worth to fix the fields
'Field_name' and 'Optimal_fieldtype' to use UTF8,
and 'Min_value' and 'Max_value' to inherit their charsets
from the original items. But it is not important,
and BINARY(N) is OK for now.
4. Tests were fixed accordingly. No new tests were
made, as the old onces cover everything.
For numeric constants we only need to add, since the parser doesn't produce
negative numbers.
For strings we only add (we actually could substract 1 if given string is a constant
and it has '-number' form but we're not doing that because
* we set max_length bigger then necessary in other cases as well.
* the current solution is simpler and safer (bigger max_length is better then cutting out)
the result takes its charset/collation
attributes from the character string,
e.g. SELECT func(NULL, _latin2'string')
now returns a latin2 result. This is
done by introducing a new derivation
(aka coercibility) level DERIVATION_IGNORABLE,
which is used with Item_null.
2. 'Pure' NULL is now BINARY(0), not CHAR(0).
I.e. NULL is now more typeless.
TIMESTAMP columns should be unsigned to preserve compatibility with 4.0
(Or else InnoDB will return different internal TIMESTAMP values when user upgrades to 4.1).
Altough this fix will introduce problems with early 4.1 -> 4.1 upgrades (tables with
TIMESTAMP field should be reloaded using mysqldump) it will allow easy 4.0 -> 4.1
upgrade (which is more important since 4.1 is still beta).
