表A
id name code
1 wang AA
1 li BB
2 zhang CC
3 huang DD
3 cai EE
3 ren FF结果要:id name code
1 wang,li AA,BB
2 zhang CC
3 huang,cai,ren DD,EE,FF
id name code
1 wang AA
1 li BB
2 zhang CC
3 huang DD
3 cai EE
3 ren FF结果要:id name code
1 wang,li AA,BB
2 zhang CC
3 huang,cai,ren DD,EE,FF
group_concat(code separator ',') code
from tb
group by id