多行查询结果合并成一个

准备数据：

CREATE TABLE TEST_GROUP_A (
  STDCODE VARCHAR2(30),
  DEMO VARCHAR2(100)

);

insert into TEST_GROUP_A values ('1001','AAA');
insert into TEST_GROUP_A values ('1001','BBB');
insert into TEST_GROUP_A values ('1002','CCC');
insert into TEST_GROUP_A values ('1001','AGE');

 

查询实现:

       Oracle数据库：

            SELECT STDCODE, WMSYS.WM_CONCAT(DEMO)
              FROM TEST_GROUP_A T
             WHERE 1 = 1
             GROUP BY STDCODE


      MySQL数据库：

            SELECT STDCODE, GROUP_CONCAT(DEMO)
              FROM TEST_GROUP_A T
             WHERE 1 = 1
             GROUP BY STDCODE