Table is specified twice, both as a target for 'UPDATE' and as a separate source for data in mysql

Question

I have below query in mysql where I want to check if branch id and year of finance type from branch_master

Answer 1

The problem I had with the accepted answer is that create a copy of the whole table, and for me wasn't an option, I tried to execute it but after several hours I had to cancel it.

A very fast way if you have a huge amount of data is create a temporary table:

1. Create TMP table

   CREATE TEMPORARY TABLE tmp_manager (branch_id bigint auto_increment primary key, year datetime null);

2. Populate TMP table

   insert into tmp_manager (branch_id, year) select branch_id, year from manager;

3. Update with join

   UPDATE manager as m, tmp_manager as tmp_m inner JOIN manager as man on tmp_m.branch_id = man.branch_id SET status = 'Y' WHERE m.branch_id = tmp_m.branch_id and m.year = tmp_m.year and m.type = 'finance';