From: Peter Brawley
> >I'd like to run a query to find the records that
> >are present in one database but not the other.
>
> See 'Compare data in two tables' at
> http://www.artfulsoftware.com/infotree/queries.php.
Thanks. That's a start.
SELECT
MIN(TableName) as TableName, id, col1, col2, col3, ...
FROM (
SELECT 'Table a' as TableName, a.id, a.col1, a.col2, a.col3, ...
FROM a
UNION ALL
SELECT 'Table b' as TableName, b.id, b.col1, b.col2, b.col3, ...
FROM b
) AS tmp
GROUP BY id, col1, col2, col3, ...
HAVING COUNT(*) = 1
ORDER BY ID;
This finds common rows. That doesn't help when the tables have about
20,000 rows and most are the same. How do I invert the query so that I
can find the 'uncommon' rows? Second, the primary key ('id' in the
example) values do not match, so how/where in the query can you specify
how to match rows from the two tables using other columns?
