Select into outfile, and then delete the selected rows

Databases
1

Hi guys.

I’ve just put together a really simple stored-procedure that will run every couple of minutes which creates an outfile:

BEGIN
	SET @sql_text = CONCAT ("SELECT `out_line` into outfile 'wms-in."
					,	DATE_FORMAT( NOW(), '%Y%m%d%H%i%s')
					,	"' LINES TERMINATED BY '\
'"
					,	" FROM jobs_out WHERE `scheduled` < now();");
	PREPARE s1 FROM @sql_text;
	EXECUTE s1;
	DROP PREPARE s1;
END

From this we’re generating a filename with a datetime stamp in the filename as required by the system that is reading it and it only reads in lines that are scheduled to be read (there is a 15 minute delay that is put on every entry via the scheduled field.)

This all works perfect, just as we need it to, but the problem that I now have is that the row stays there forever. I need to remove it once it’s been read in to the file. How best to do this?

Cheers

2

A quick thought: If I was to select the PK of every row that I’ll want in the outfile, and put the PK in to a variable in a format suitable to go in to an IN() function, I could then do the above query but the WHERE part of the query would be “WHERE id IN(@invar)”, which I could then use again in a delete query. Is that a sensible way to do it?

3

No, forget that one, you can’t return more than one result at a time in the SP.

I worked it out myself by starting off setting @timenow as now(), then selecting everything where the time is < @timenow, and then deleting every record that is < @timenow. Seems to work a treat