I have two tables, both with ~30,000 rows. Anywhere where
b.comments is not null, I want to overwrite
b.comments' data. Seems simple enough - but my query has been running for 45 minutes and I don't think it's working. There about 3,000 values in
b that are not null - so a max of 3,000 updates.
I know that syntactically this is fine, but I'm wondering if there is a different way I should be writing this query as I cannot seem to get it to run unless I also add in something like
...and batch_id = 12345 to get the number of records down to 1.
UPDATE temp3 a INNER JOIN temp2 b ON a.batch_id = b.batch_id and a.batch_li = b.batch_li SET a.comments = b.comments WHERE b.comments is not null;