Question

如果我有这张桌子：

+----+--------+--------+--------+--------+
| ID | Field1 | Field2 | Field3 | Field4 |
+----+--------+--------+--------+--------+
| 1  | Foo    |        | Bar    | Baz    |
| 2  |        | Baz    |        |        |
| 3  |        | Dolor  | Bob    |        |
| 4  | Lorem  |        |        | Test   |
| 5  |        | Ipsum  |        |        |
| 6  | Foo    | Bar    | Baz    | Test   |
+----+--------+--------+--------+--------+

如何选择单行，并将非空列作为列表返回？

例如，如果我有这个（不完整的）陈述：SELECT [...] AS Columns FROM [MyTable] WHERE ID = 1，我希望看到这个结果：

+---------+
| Columns |
+---------+
| Foo     |
| Bar     |
| Baz     |
+---------+

这个select语句看起来怎么样？

Answer 1

试试这个：

SELECT  x.Field
FROM YourTable t
CROSS APPLY 
(
    VALUES
        (t.Field1),
        (t.Field2),
        (t.Field3),
        (t.Field4)
) x (Field);
WHERE t.ID = 1 AND field IS NOT NULL

Answer 2

试试这个，

select feild from 
(select * from @t where id=1)t4
unpivot(orders for feild in(Field1,Field2,Field3,Field4))pvt

从行中选择非空列作为列表

2 个答案: