What error did you get? I just tested two tables and it works.
CREATE COLUMN TABLE T1 (
MATERIAL VARCHAR(10),
SOURCE_PLANT VARCHAR(10)
);
INSERT INTO T1 VALUES ('M1', 'SYW1');
INSERT INTO T1 VALUES ('M2', 'SWW1');
INSERT INTO T1 VALUES ('M4', 'AABB');
INSERT INTO T1 VALUES ('M5', 'AEW1');
INSERT INTO T1 VALUES ('M6', 'AYW1');
INSERT INTO T1 VALUES ('M7', 'AABB');
CREATE COLUMN TABLE T2 (
MATERIAL VARCHAR(10),
RECEIVING_PLANT VARCHAR(10),
SOURCE_PLANT VARCHAR(10),
PROC_TYPE VARCHAR(10)
);
INSERT INTO T2 VALUES ('M1', 'AEW1', 'SYW1', 'SY');
INSERT INTO T2 VALUES ('M2', 'AYW1', 'SWW1', 'SW');
INSERT INTO T2 VALUES ('M3', 'AZW1', 'DWW1', 'DW');