db2 coalesce with concat columns replacing with null still shows special characters

Hi,


I am creating a view where in a column say colC definition is based on concat of two other columns that are separated by ';' ( v.colA||';'||v.colB ). The requirement is that if the value of the concat'd columns are null it should return null. In the above case it happens to return ';' even if the result is null. I tried using coalesce but still it's giving same error.

coalesce(concat(concat(v.colA, ';'), v.colB),'')

coalesce(v.colA||';'||v.colB, NULL)

case when v.colA||v.colB is NULL then NULL else
v.colA||';'||v.colB END,

Nothing seems to replace ';' .

Can any one help,

Thanks