UPDATE table1 SET C = (select min(c) from table2 where table2.a = table1.a);
UPDATE table1 SET C = (select min(c) from table2 where table2.a = table1.a);
UPDATE TABLE1 A SET A.COLUMN1 = (SELECT B.COLUMN1 FROM TABLE2 B WHERE B.COLUMN_KEY2 = A.COLUMN_KEY1 AND B.DATE1 >= (SELECT MIN(C.DATE1) FROM TABLE3 C WHERE C.COLUMN_KEY2=B.COLUMN_KEY2))
SET C = (select min(c) from table2 where table2.a = table1.a);
UPDATE table1 SET C = (select min(c) from table2 where table2.a = table1.a);
SET A.COLUMN1 = (SELECT B.COLUMN1
FROM TABLE2 B
WHERE B.COLUMN_KEY2 = A.COLUMN_KEY1
AND B.DATE1 >= (SELECT MIN(C.DATE1) FROM TABLE3 C WHERE C.COLUMN_KEY2=B.COLUMN_KEY2))