Query Q_tb1
SELECT Tb1.MaID, 1 as ztyp,Da.Ngay, Tb1.GT AS A1
FROM Tb1 INNER JOIN Da ON Tb1.GT = Da.C1
UNION SELECT Tb1.MaID,2, Da.Ngay, Tb1.GT
FROM Tb1 INNER JOIN Da ON Tb1.GT = Da.C2
UNION SELECT Tb1.MaID, 3,Da.Ngay, Tb1.GT
FROM Tb1 INNER JOIN Da ON Tb1.GT = Da.C3
UNION SELECT Tb1.MaID,4...