sql - Decompose one row into multi rows according conditions -

i have table :

id    a_kode    b_kode    c_kode -------------------------------- 1     10        12        0 2     15        0         0 3     0         16        17 4     0         0         0 

require query provide result :

id    kode  ------------ 1     10 1     12 2     15 3     16 3     17 4     0 

first need union rows exists not 0 value , add rows 0 columns values zeroes.

select id,a_kode kode t a_kode<>0 union select id,b_kode kode t b_kode<>0 union select id,c_kode kode t c_kode<>0 union select id,0 kode t a_kode=0 , b_kode=0 , c_kode=0