SELECT COALESCE((Select Top 1 dien_giai From ct70 where 1=0),NULL) as dien_giai2, ...
Thông qua hàm COALESCE
https://stackoverflow.com/questions/5465245/create-a-nullable-column-using-sql-server-select-into
SELECT COALESCE((Select Top 1 dien_giai From ct70 where 1=0),NULL) as dien_giai2, ...
Thông qua hàm COALESCE
https://stackoverflow.com/questions/5465245/create-a-nullable-column-using-sql-server-select-into