INSERT tbl_A WITH (TABLOCK) (col, col2)
SELECT col, col2
FROM tbl_B
WHERE NOT EXISTS (SELECT col FROM tbl_A A2 WHERE A2.col = tbl_B.col)
OPTION (HASH JOIN, MAXDOP 1);
INSERT tbl_A WITH (TABLOCK) (col, col2)
SELECT col, col2
FROM tbl_B
WHERE NOT EXISTS (SELECT col FROM tbl_A A2 WHERE A2.col = tbl_B.col)
OPTION (MAXDOP 1);