Question

我正在使用具有表x的SQL Server数据库。

表：x

x_id    Type        Text        ID
-------------------------------------------
| 1  |  Type1  |    txt1   |    id1
| 2  |  Type2  |    txt2   |    id2
| 3  |  Type3  |    txt3   |    id1
| 4  |  Type3  |    txt4   |    id3

这里，每个ID可以有Type1，Type2，Type3等不同的文本。

我需要生成包含字段ID，Type1_exists，Type2_exists，Type3_exists，Type1_Text，Type2_Text，Type3_Text的报告，其中存在列应该说明ID是否具有该文本（Y / N）。如果ID的记录类型为＆＃34; Type1＆＃34;然后Type1_exists值应为＆＃34; Y＆＃34;否则＆＃34; N＆＃34;。

所以，我期待的样本结果是

ID    Type1_Exists  Type1_Text   Type2_Exists  Type2_Text  Type3_Exists Type3_Text
---------------------------------------------------------------------
| id1  |      Y     | txt1   |        N        |      |     Y           |  txt3
| id2  |      N     |        |        Y        | txt2 |     N           |  
| id3  |      N     |        |        N        |      |     Y           |  txt4

Answer 1

您可以使用PIVOT或条件聚合

PIVOT：

SELECT 
    [ID],
    [Type1_Exists] = CASE WHEN [Type1] IS NULL THEN 'N' ELSE 'Y' END,
    [Type1_Text] = [Type1],
    [Type2_Exists] = CASE WHEN [Type2] IS NULL THEN 'N' ELSE 'Y' END,
    [Type2_Text] = [Type2],
    [Type3_Exists] = CASE WHEN [Type3] IS NULL THEN 'N' ELSE 'Y' END,
    [Type3_Text] = [Type3] 

FROM (
    SELECT [ID], [Type], [Text]
    FROM x 
) t 
PIVOT (
    MAX([Text])
    FOR [Type] IN ([Type1],[Type2],[Type3])
) p

有条件的聚合：

SELECT  
    [ID],
    MAX(CASE WHEN [Type] = 'Type1' THEN 'Y' ELSE 'N' END) AS [Type1_Exists],
    MAX(CASE WHEN [Type] = 'Type1' THEN [Text] END) AS [Type1_Text],
    MAX(CASE WHEN [Type] = 'Type2' THEN 'Y' ELSE 'N' END) AS [Type2_Exists],
    MAX(CASE WHEN [Type] = 'Type2' THEN [Text] END) AS [Type2_Text],
    MAX(CASE WHEN [Type] = 'Type3' THEN 'Y' ELSE 'N' END) AS [Type3_Exists],
    MAX(CASE WHEN [Type] = 'Type3' THEN [Text] END) AS [Type3_Text]
FROM 
    x 
GROUP BY [ID]

Answer 2

一种方法是将表连接到自身，在ON子句中有限制为每种类型提取行，如下所示：

select distinct x0.ID, 
case when x1.Text is null then 'N' else 'Y' end type1_exists,
x1.Text type1_text, 
case when x2.Text is null then 'N' else 'Y' end type2_exists,
x2.Text type2_text,
case when x3.Text is null then 'N' else 'Y' end type3_exists,
x3.Text type3_text, 
case when x4.Text is null then 'N' else 'Y' end type4_exists,
x4.Text type4_text
from x x0 left join x x1 on x0.ID = x1.ID and x1.Type = 'Type1'
left join x x2 on x0.ID = x2.ID and x2.Type = 'Type2'
left join x x3 on x0.ID = x3.ID and x3.Type = 'Type3'
left join x x4 on x0.ID = x4.ID and x4.Type = 'Type4'
order by 1;

SQL Server也明确支持使用PIVOT的交叉表查询。

SQL Server查询以根据表数据生成自定义报告

2 个答案: