On 11/06/2015 03:04 PM, vitaly numenta wrote:
> Hi, I am using sqlalchemy core with the mysql dialect. Mysql supports
> DELETE with ORDER BY and LIMIT:
>
> DELETE [LOW_PRIORITY] [QUICK] [IGNORE] FROM tbl_name
> [PARTITION (partition_name,...)]
> [WHERE where_condition]
> [ORDER BY ...]
> [LIMIT row_count]
>
>
> However, I can't seem to figure out how to do this via sqlalchemy core.
emit the exact SQL you want as a string:
conn.execute("DELETE .... WHERE ... ORDER BY ... LIMIT")
the query is MySQL specific in any case so you wouldn't need to worry
about portability.
I seem to recall a ticket asking for this feature but at the moment I
can only find one referring to DELETE FROM .. JOIN for MySQL.
> I have a really large table from which I need to garbage-collect old
> rows now and then. When I try to do it all in one operation, I end up
> getting "Lock wait timeout exceeded; try restarting transaction", so I
> wanted to take advantage of order_by and limit to do this incrementally,
> but mysqlalchemy won't let me.
>
> Please help.
>
> Thank you,
> Vitaly
>
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