php - sql table to update nulled column -

this question has answer here:

• sql table how multliply array of numbers fetched sql table , stored array , return 3 answers

table given below

id         country       person        money     sum  1           uk           john          2010      null 2           usa          henry         120       null 3           rus          neko          130       null 4           ger          suka          110       null 7           can          beater        1450      null 8           usa          lusi          2501      null 

each money column multiply 2 , stored corresponding sum column how, given below

id         country       person        money     sum  1           uk           john          2010      4020 2           usa          henry         120       240 3           rus          neko          130       260 4           ger          suka          110       220 7           can          beater        1450      2900 8           usa          lusi          2501      5002 

you want update field using expression this.

update `tablename` set `sum` = `money` * 2 `sum` null; 

if want happen indescriminately can drop portion of update like:

update `tablename` set `sum` = `money` * 2;