Konstantin Osipov wrote:
> * Davi Arnaut <davi@stripped> [07/10/08 16:57]:
>> ChangeSet@stripped, 2007-10-08 08:38:07-03:00, davi@stripped +6 -0
>> Bug#27525 table not found when using multi-table-deletes with aliases over
> several databas
>>
>
> 1) There are two syntaxes of MULTI-DELETE:
> DELETE <list> FROM <list> WHERE ...
> and
> DELETE FROM <list> USING <list> WHERE ...
>
> Both should be fixed and covered with tests.
Thinking more about it, I believe some cases that the cparser is
accepting are bugs and we should disallow aliases in the first <list>
and always threat then as table names. It's not worth the trouble, alias
are only really worth on the second list where they can be used in the
where_condition. For example, the parser is accepting weird/ambiguous
statements like:
DELETE a1 FROM db1.t1 AS a1, db2.t2 AS a1;
Resolving this kind of ambiguity would require multiple passes over the
list and serves no purpose what-so-ever. Can we scrap alias support from
the table name list?
> 2) Ambiguous cases should be taken care of and covered with tests
> (an error should be produced):
>
> DELETE t1, t2 FROM db1.t1, db2.t1, t2, db2.t2 ...
OK.
> 3) Please also add tests that demonstrate the conflict resolution
> between an assigned alias and a database name:
>
> DELETE t1, db1.t1 FROM t2 as t1, db1.t1 -- ?
No, this one is another example we shouldn't allow the alias. This query
should mean:
DELETE selected_db.t1, db1.t1 FROM selected_db.t2 AS t1, db1.t1 --
and spill out a error (non-unique or not in the from list, depending on
the selected_db).
Regards,
--
Davi Arnaut, Software Engineer
MySQL Inc, www.mysql.com
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