Get previous value after update - MySql

Question

I have a table which includes id and name

---    -----  
id     name
---    -----
1      pete

My scenarios looks like this

$sql         


        

Answer 1

You cannot fetch the previous name unless you save it to your table as a backup.

If you want to achieve this create one more column in your table and save the current name before updating to the new one.

Answer 2

If you are updating one row and you want the previous name, you can use variables:

set @prevname = '';

update table_name
    set name = if(@prevname := name, 'Alan', 'Alan')
    where id = 1;

select @prevname;

However, I suspect that you really want a slowly changing dimension, and update is not the right operation.

Answer 3

You can do that by using the OLD and NEW keywords on a trigger on your table.

Although, i see that you tagged your post as php and I guess you want to get the old value in php, and to do this, you have to do a SELECT before the UPDATE to get the old name, and another SELECT after the UPDATE to get the new name.