Question

我有一个Select语句，需要在其中添加IF / ELSE语句，

IF @P_COUNT = 'X' 
    show the Count(*) FROM SELECT statement 
ELSE 
    I need to return table from the SELECT statement results

目前这是我所拥有的，但无法正常工作。

@P_COUNT            VARCHAR(1)

IF @P_COUNT = 'X' 
    SELECT COUNT(*) 
    ELSE SELECT * FROM (
   (SELECT ... UNION ... ) AS A
    LEFT JOIN 
   (SELECT A, B, C, D FROM Table_1) AS B
    ON WHERE A.XX = B.XX
    LEFT JOIN 
   (SELECT A, B, C, D FROM Table_1) AS C
    ) AS D

当前结果：

IF @P_COUNT = 'X', RESULT => 1 Expected => 26017
IF @P_COUNT = '', RESULT => returns proper Select statement.

预先感谢您的帮助！

Answer 1

这是您想要的吗？

IF @P_COUNT = 'X' 
BEGIN
   SELECT COUNT(*) 
   FROM (
   (SELECT ... UNION ... ) AS A
    LEFT JOIN 
   (SELECT A, B, C, D FROM Table_1) AS B
    ON WHERE A.XX = B.XX
    LEFT JOIN 
   (SELECT A, B, C, D FROM Table_1) AS C
    ) AS D 
END
ELSE
BEGIN
   SELECT * FROM (
   (SELECT ... UNION ... ) AS A
    LEFT JOIN 
   (SELECT A, B, C, D FROM Table_1) AS B
    ON WHERE A.XX = B.XX
    LEFT JOIN 
   (SELECT A, B, C, D FROM Table_1) AS C
    ) AS D 
END;

您有两个独立的SELECT查询。他们每个人都需要一个FROM子句。

SQL IF / ELSE语句

1 个答案: