Oracle。 感谢这篇文章PL/SQL -在Where in子句中使用“List”变量

我把我的示例语句放在一起，以便轻松地手动输入值(测试人员在测试应用程序时重用):

WITH prods AS (
    SELECT column_value AS prods_code 
    FROM TABLE(
        sys.odcivarchar2list(
            'prod1', 
            'prod2'
        )
    )
)
SELECT * FROM prods

在Oracle中

SELECT
  CASE
    WHEN level = 1
    THEN 'HI'
    WHEN level = 2
    THEN 'BYE'
  END TEST
FROM dual
  CONNECT BY level <= 2;

下面介绍如何使用DB2的XML特性来实现这一点

SELECT *
FROM
XMLTABLE ('$doc/ROWSET/ROW' PASSING XMLPARSE ( DOCUMENT '
<ROWSET>
  <ROW>
    <A val="1" /> <B val="2" /> <C val="3" />
  </ROW>
  <ROW>
    <A val="4" /> <B val="5" /> <C val="6" />
  </ROW>
  <ROW>
    <A val="7" /> <B val="8" /> <C val="9" />
  </ROW>
</ROWSET>
') AS "doc"
   COLUMNS 
      "A" INT PATH 'A/@val',
      "B" INT PATH 'B/@val',
      "C" INT PATH 'C/@val'
) 
AS X
;

下面的裸值命令为我在PostgreSQL工作:

VALUES (1,2,3), (4,5,6), (7,8,9)

select (level - 1) * row_dif + 1 as a, (level - 1) * row_dif + 2 as b, (level - 1) * row_dif + 3 as c
    from dual 
    connect by level <= number_of_rows;

就像这样

select (level - 1) * 3 + 1 as a, (level - 1) * 3 + 2 as b, (level - 1) * 3 + 3 as c
    from dual 
    connect by level <= 3;

下面是一种直接用MySQL请求SELECT创建自定义行的方法:

SELECT ALL *
FROM (
    VALUES
        ROW (1, 2, 3),
        ROW (4, 5, 6),
        ROW (7, 8, 9)
) AS dummy (c1, c2, c3)

给我们一个表假人:

c1   c2   c3
-------------
 1    2    3
 4    5    6
 7    8    9

用MySQL 8测试