MYSQL – Selecting and updating a table column incremental
Pentru a selecta o coloana incremental, incepand de la o anumita valoare (in acest caz 0):
SELECT @rownum:=@rownum+1 AS rank FROM `table_name`, (SELECT @rownum:=0) r WHERE 1
Pentru a updata o coloana incremental (adica de la 0 la X)
UPDATE table_name SET column_name = (SELECT @rownum:=@rownum+1 AS newid FROM (SELECT @rownum:=0) r )
Daca se doreste si pastrarea ordinii initiale:
UPDATE table_name t SET column_name = (SELECT @rownum:=@rownum+1 AS newid FROM (SELECT @rownum:=0) r ) ORDER BY t.column_name