OceanBase MERGE

MERGE [hint_options] 
         INTO table_factor [opt_alias] 
        USING table_factor [opt_alias]
            ON '(' expr ')'
    [merge_update_clause]
        [merge_insert_clause] 
    
merge_update_clause:
    WHEN MATCHED THEN UPDATE SET update_asgn_list [WHERE expr] [DELETE WHERE expr]

merge_insert_clause:
    WHEN NOT MATCHED THEN INSERT opt_insert_columns VALUES '(' insert_vals ')' [WHERE expr]

CREATE TABLE t1 (c1 INT, c2 INT);
CREATE TABLE t2 (c1 INT, c2 INT);

INSERT INTO t1 VALUES(0, 0);
INSERT INTO t1 VALUES(1, null);
INSERT INTO t1 VALUES(2, null);
INSERT INTO t2 VALUES(1, 1);
INSERT INTO t2 VALUES(2, 20); 
INSERT INTO t2 VALUES(3, 3);
INSERT INTO t2 VALUES(4, 40);

obclient>MERGE INTO t1 USING t2 ON (t1.c1 = t2.c1)
       WHEN MATCHED THEN UPDATE SET c2 = t2.c2 where t1.c2 IS NULL DELETE 
       WHERE t1.c2 >= 10 WHEN NOT MATCHED THEN INSERT VALUES(t2.c1, t2.c2) 
       WHERE t2.c2 < 10;
Query OK, 3 rows affected (0.02 sec)

obclient>SELECT * FROM t1;
+------+------+
| C1   | C2   |
+------+------+
|    0 |    0 |
|    1 |    1 |
|    3 |    3 |
+------+------+
3 rows in set (0.00 sec)