BLOB fields did not work as grouping keys at all, they were assigned
value NULL for any value, be it NULL or not. The fix is in the
rowaggregation.cpp in the initMapping(), a switch/case branch was added
to handle BLOB field copying there.
Also, TEXT columns did not distinguish between NULL and empty string in
the grouping algorithm, now they do. The fix is in the equals()
function, now we specifically check for isNull() equality between
values.
Server expands ut8_XXX aliases to utf8mb3_XXX or utf8mb4_XXX depending
on the UTF8_IS_UTF8MB3 setting in the OLD_MODE environment variable.
Server already has the necessary code implemented in the get_utf8_flag()
method of class THD. There are several uses of this flag and all we have
to do to be in line with server is to use it.
This patch does that for DDL as work on MCOL-5705 uncovered some
problems in that area.
The fix is simple: enable subtotals in single-phase aggregation and
disable parallel processing when there are subtotals and aggregation is
single-phase.
The purpose of this changeset is to obtain list of partitions from
SELECT_LEX structure and pass it down to joblist and then to
CrossEngineStep to pass to InnoDB.
This patch introduces an internal aggregate operator SELECT_SOME that
is automatically added to columns that are not in GROUP BY. It
"computes" some plausible value of the column (actually, last one
passed).
Along the way it fixes incorrect handling of HAVING being transferred
into WHERE, window function handling and a bit of other inconsistencies.
The most important fix here is the fix of possible buffer overrun in
DATEFORMAT() function. A "%W" format, repeated enough times, would
overflow the 256-bytes buffer for result. Now we use ostringstream to
construct result and we are safe.
Changes in date/time projection functions made me fix difference between
us and server behavior. The new, better behavior is reflected in changes
in tests' results.
Also, there was incorrect logic in TRUNCATE() and ROUND() functions in
computing the decimal "shift."
* MCOL-4234: improve GROUP BY and ORDER BY interaction (#3194)
This patch fixes the problem in MCOL-4234 and also generally improves
behavior of GROUP BY.
It does so by introducing a "dummy" aggregate and by wrapping columns
into it. This allows for columns that are not in GROUP BY to be used
more freely, for example, in SELECT * FROM tbl GROUP BY col - all
columns that are not "col" will be wrapped into an aggregate and query
will proceed to execution.
The dummy aggregate itself does nothing more than remember last value
passed into it.
There also an additional error message that tries to explain what types
of expressions can be wrapped into an aggregate.
* MCOL-5772: incorrect ORDER BY ordering for a columns not in GROUP BY (#3214)
When ORDER BY column is not in GROUP BY, is not an aggregate and there
is a SELECT column that is also not an aggregate, there was a problem:
ordering happened on the SELECTed column, not ORDERed one.
This patch fixes that particular problem and also performs some tidying
around newly added aggregate.
---------
Co-authored-by: Leonid Fedorov <79837786+mariadb-LeonidFedorov@users.noreply.github.com>
