Question

表格：

CREATE TABLE EMPDetails
(
    ID int,
    EmpName varchar(20),
    ColumnName varchar(20),
    ColumnValue varchar(20)
);

记录：

INSERT INTO EMPDetails Values(1,'S','Company','Microsoft');
INSERT INTO EMPDetails Values(1,'S','Profession','Database');
INSERT INTO EMPDetails Values(1,'S','Location','USA');
INSERT INTO EMPDetails Values(1,'S','Company','Unisys');
INSERT INTO EMPDetails Values(1,'S','Company','TATA');

INSERT INTO EMPDetails Values(2,'U','Company','Microsoft');
INSERT INTO EMPDetails Values(2,'U','Profession','Software');
INSERT INTO EMPDetails Values(2,'U','Location','UK');
INSERT INTO EMPDetails Values(2,'U','Company','DXC');
INSERT INTO EMPDetails Values(2,'U','Company','AOL');

INSERT INTO EMPDetails Values(3,'R','Company','Microsoft');
INSERT INTO EMPDetails Values(3,'R','Profession','Software');
INSERT INTO EMPDetails Values(3,'R','Location','UK');
INSERT INTO EMPDetails Values(3,'R','Company','AOL');

我的尝试：

SELECT * FROM EMPDetails
WHERE (ColumnName = 'Company' AND ColumnValue = 'Microsoft') AND 
      (ColumnName = 'Profession' AND ColumnValue = 'Software')

预期输出

--------------------------------------------      
ID  EmpName     ColumnName      ColumnValue
--------------------------------------------      
2   U           Company         Microsoft
2   U           Profession      Software
3   R           Company         Microsoft
3   R           Profession      Software

Answer 1

您需要根据条件数计算其出现次数，并将结果连接到表格本身。

SELECT  a.*
FROM    EMPDetails a
        INNER JOIN
        (
            SELECT  ID, EmpName
            FROM    EMPDetails
            WHERE   (ColumnName = 'Company' AND ColumnValue = 'Microsoft') OR
                    (ColumnName = 'Profession' AND ColumnValue = 'Software')
            GROUP   BY ID, EmpName
            HAVING  COUNT(*) = 2
        ) b ON a.ID = b.ID
                AND a.EmpName = b.EmpName
WHERE (a.ColumnName = 'Company'    AND a.ColumnValue = 'Microsoft') OR
      (a.ColumnName = 'Profession' AND a.ColumnValue = 'Software')

这里是Demo。

Answer 2

另一个但与其他人相似

SELECT  a.*
  FROM  EMPDetails a
  JOIN ( SELECT  ID
           FROM  EMPDetails
          WHERE  ColumnName = 'Company'    AND ColumnValue = 'Microsoft'  
         intersect 
         SELECT  ID
           FROM  EMPDetails
          WHERE  ColumnName = 'Profession' AND ColumnValue = 'Software'
       ) b 
    ON a.ID = b.ID
 where (ColumnName = 'Company'    AND ColumnValue = 'Microsoft') 
    OR (ColumnName = 'Profession' AND ColumnValue = 'Software')

Answer 3

一种解决方案是使用OR和EXISTS

SELECT * FROM EMPDetails e1
WHERE (ColumnName = 'Company' AND 
       ColumnValue = 'Microsoft' AND
       EXISTS(SELECT * FROM EMPDetails e2
              WHERE ColumnName = 'Profession' AND 
                    ColumnValue = 'Software' AND 
                    e1.id = e2.id) 
      ) OR
      (ColumnName = 'Profession' AND 
       ColumnValue = 'Software' AND 
       EXISTS(SELECT * FROM EMPDetails 
              WHERE ColumnName = 'Company' AND 
                    ColumnValue = 'Microsoft' AND 
                    e1.id = e2.id)))

在关系数据库中，列（即ColumnName）在一行中有两个不同的值是不可能的，因此，您的结果始终为空。

Answer 4

使用INTERSECT查找包含所需组合的ID：

SELECT * FROM EMPDetails
WHERE ((ColumnName = 'Company' AND ColumnValue = 'Microsoft') OR 
       (ColumnName = 'Profession' AND ColumnValue = 'Software')) AND
      ID IN (select id from EMPDetails
             WHERE (ColumnName = 'Company' AND ColumnValue = 'Microsoft')
             INTERSECT
             select id from EMPDetails
             WHERE (ColumnName = 'Profession' AND ColumnValue = 'Software'))

Answer 5

另一种方法

select
    ID, EmpName, ColumnName, ColumnValue
from (
    SELECT
        *, total = sum(cnt) over (partition by ID, EmpName)
    FROM 
        EMPDetails
        cross apply (
            select cnt = case 
                    when ColumnName  = 'Company' and ColumnValue = 'Microsoft' then 1
                    when ColumnName  = 'Profession' and ColumnValue = 'Software' then 10
                    else 0
                end) q
) t
where
    cnt > 0
    and total / 10 > 0
    and total % 10 > 0

SQL Server 2008 R2：使用AND运算符在同一列上的多个条件

5 个答案: