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【DM版本】:DM8
【操作系统】：windwos
【CPU】:x86
【问题描述】*：
执行文档中 merge into 示例代码时，一直不结束

DROP TABLE T1;
DROP TABLE T2;
CREATE TABLE T1 (C1 INT,  C2 VARCHAR(20));
CREATE TABLE T2 (C3 INT,  C4 VARCHAR(20));
INSERT INTO T1 VALUES(1,'T1_1');
INSERT INTO T1 VALUES(2,'T1_2');
INSERT INTO T1 VALUES(3,'T1_3');
INSERT INTO T2 VALUES(2,'T2_2');
INSERT INTO T2 VALUES(4,'T2_4');
COMMIT;

MERGE INTO T1 USING T2 ON (T1.C1=T2.C3) 
WHEN MATCHED THEN UPDATE SET T1.C2=T2.C4 
WHEN NOT MATCHED THEN INSERT (C1,C2) VALUES(T2.C3, T2.C4);