Compare 2 tables, insert non existing values only...

[kamy99]

Hi:

I try to simplify my problem here 😃

We have a table that needs to be updated regularly from other tables.
Out main table is user_data

We have another table, with corresponding columns to user_data, it's called users_tmp.

I need to compare the tables, then only insert into user_data rows that do not already exist.
I'm using LEFT JOIN like this:

SELECT
                tut.user_id as user_id,
                tut.member_id as member_id,
                tut.ip as ip,
                tut.show_id as show_id,
                tut.diffuser_id as diffuser_id
            FROM
                users_tmp tut
            LEFT JOIN
                user_data tu ON tu.member_id = tut.member_id AND tu.ip = tut.ip AND tu.diffuser_id = tut.show_id AND tu.diffuser_id = tut.show_id

I need an optimized script/method to do this, as I get over 500,000 rows in each table.....
Any ideas?

tx
Kamy

[johanafm]

It's a left join from users_tmp to user_data, which means that for any record in users_tmp that have no related data in user_data, all selected fields in user_data will be supplied with null values, which means that you can

WHERE  tu.member_id IS NULL

to only retain such rows.