mysql - SQL Select/Introduce adding new values after every 3 rows -

my requirement wanted give new values column after every 3 items/rows in table. db table this.

a   b   c ---------- a1  b1  c1 a2  b2  c2 a3  b3  c3 a4  b4  c4 a5  b5  c5 a6  b6  c6 a7  b7  c7 

i wanted add new column d new value changes every 3 rows view

a   b   c  d ------------ a1  b1  c1 d1 a2  b2  c2 d1 a3  b3  c3 d1 a4  b4  c4 d2 a5  b5  c5 d2 a6  b6  c6 d2 a7  b7  c7 d3 

is possible sql select statement?