How to get affected rows in previous MySQL operation?
mysql, php, sql
Solution
It can be efficiently and simply achieved with the following:
select * from mytable where column3="a_variable" and status != 2;
update mytable set status=2 where column3="a_variable";
The result of the first query are the rows that are going to change, and the second query actually changes them.
If this is a high performance system, you may need to take special care with transactions to prevent a new row slipping in between those 2 queries.
Problem
mysql_affected_rows is to get number of affected rows in previous MySQL operation, but I want to get affected rows in previous MySQL operation. For example: ``` update mytable set status=2 where column3="a_variable"; ``` Before this operation, status of some rows is already 2, and I want to get affected rows in previous MySQL operation, you can not get it by issuing a query of ``` select * from mytable where status=2 ``` So how to do this work?