Question

UPDATED:

I have some table with sync_numbers, like this:

---------------------
id    | sync_number  
---------------------
   1  |     1
   2  |     1
   3  |     1
   4  |     1

now I want to set sync_number to its maximum value + 1 but do this for each row, like this:

---------------------
id    | sync_number  
---------------------
   1  |     2
   2  |     3
   3  |     4
   4  |     5

How can I do this?

I’ve tried to do something like this:

UPDATE u_shop SET sync_number = ((SELECT selected_value FROM (SELECT MAX(sync_number) AS selected_value FROM u_shop) AS sub_selected_value) + 1);

but this places the same values to all rows which is not that I need.

Answer 1

This should work:

UPDATE u_shop
inner join (SELECT @row := MAX(sync_number) FROM u_shop) r
SET sync_number = @row := @row + 1