Sql查询多行列中字符串的串联

Question

我有表e

eId FName LName Type  SubType
  1  a     aa    1    S11a
  1  a     aa    1    S12a
  1  a     aa    1    S13a
  1  a     aa    3    S31a
  1  a     aa    3    S32a
  2  b     bb    1    S11b
  2  b     bb    1    S12b
  2  b     bb    3    S31b
  2  b     bb    3    S32b

我想得到一张这样的桌子

eId    FName   LName   SubType1         SubType2
1       a       aa     S11a;S12a;S13a   S31a;S32a
2       b       bb     S11b;S12b         S31b;S32b

换句话说，我想运行一个sql查询，它给我一个员工的子类型组，作为类型1和类型2的两列。我试图在sql查询中使用STUFF命令但是没有成功。 这是我写的查询，但它不起作用。 基本上它为SubType列提供了Null值。

    SELECT e1.eId, e1.FName, e1.LName
, STUFF((
        SELECT N'; ' + [SubType]
        FROM e e2
        WHERE e1.eId = e2.eId 
            AND e1.FName = e2.FName 
            AND e1.LName = e2.LName         
            AND e1.[Type] = e2.[Type]           
            AND e1.[Type] = 1
        FOR XML PATH ('')), 1, 2, '') AS SubType1

, STUFF((
        SELECT N'; ' + [SubType]
        FROM e e2
        WHERE e1.eId = e2.eId 
            AND e1.FName = e2.FName 
            AND e1.LName = e2.LName         
            AND e1.[Type] = e2.[Type]           
            AND e1.[Type] = 3
        FOR XML PATH ('')), 1, 2, '') AS SubType2 
FROM e e1
GROUP BY e1.eId, e1.FirstName, e1.LastName, e1.[Type]

Answer 1

嗯。 group by . . . type group by . . . type group by . . . type是可疑的。 也许这会奏效：

SELECT e1.eId, e1.FName, e1.LName,
       STUFF((SELECT N'; ' + [SubType]
              FROM e e2
              WHERE e1.EmployeeId = e2.EmployeeId AND
                    e2.[Type] = 1
              FOR XML PATH ('')
             ), 1, 2, '') AS SubType1,
       STUFF((SELECT N'; ' + [SubType]
              FROM e e2
              WHERE e1.EmployeeId = e2.EmployeeId AND
                    e2.[Type] = 3
              FOR XML PATH ('')
             ), 1, 2, '') AS SubType1
FROM e e1
GROUP BY e1.eId, e1.FirstName, e1.LastName;

我还认为对名称的比较是多余的，所以我删除了它们。

Answer 2

您的查询中存在多个问题。

1-您正在使用的列名称不正确，在您选择使用FName和LName和Group by您使用的是FirstName和LastName 。

2- EmployeeId列是eId ，在一个地方你唱歌eId和另一个你正在使用EmployeeId地方

3- Type不在选中，它不能成为group by一部分。

以下查询应该有效。

SELECT e1.eId, e1.FName, e1.LName,
       STUFF((SELECT N'; ' + [SubType]
              FROM e e2
              WHERE e1.[eId] = e2.[eId] AND
                    e2.[Type] = 1
              FOR XML PATH ('')
             ), 1, 2, '') AS SubType1,
       STUFF((SELECT N'; ' + [SubType]
              FROM e e2
              WHERE e1.[eId] = e2.[eId] AND
                    e2.[Type] = 3
              FOR XML PATH ('')
             ), 1, 2, '') AS SubType1
FROM e e1
GROUP BY e1.eId, e1.FName, e1.LName;

DEMO

编辑：

您也可以尝试以下操作，这可以清楚地将组与您的子查询隔离开来。

SELECT *,
 STUFF((SELECT N'; ' + [SubType]
              FROM e e2
              WHERE e3.[eId] = e2.[eId] AND
                    e2.[Type] = 1
              FOR XML PATH ('')
             ), 1, 2, '') AS SubType1,
       STUFF((SELECT N'; ' + [SubType]
              FROM e e2
              WHERE e3.[eId] = e2.[eId] AND
                    e2.[Type] = 3
              FOR XML PATH ('')
             ), 1, 2, '') AS SubType1
FROM
(
  SELECT e1.eId, e1.FName, e1.LName   
  FROM e e1
  GROUP BY e1.eId, e1.FName, e1.LName
)e3

Answer 3

试试这个......

表脚本和示例数据

CREATE TABLE [TableName](
    [eId] [int] NULL,
    [FName] [nvarchar](50) NULL,
    [LName] [nvarchar](50) NULL,
    [Type] [int] NULL,
    [SubType] [nvarchar](50) NULL
)

INSERT [TableName] ([eId], [FName], [LName], [Type], [SubType]) VALUES (1, N'a', N'aa', 1, N'S11a')
INSERT [TableName] ([eId], [FName], [LName], [Type], [SubType]) VALUES (1, N'a', N'aa', 1, N'S12a')
INSERT [TableName] ([eId], [FName], [LName], [Type], [SubType]) VALUES (1, N'a', N'aa', 1, N'S13a')
INSERT [TableName] ([eId], [FName], [LName], [Type], [SubType]) VALUES (1, N'a', N'aa', 3, N'S31a')
INSERT [TableName] ([eId], [FName], [LName], [Type], [SubType]) VALUES (1, N'a', N'aa', 3, N'S32a')
INSERT [TableName] ([eId], [FName], [LName], [Type], [SubType]) VALUES (2, N'b', N'bb', 1, N'S11b')
INSERT [TableName] ([eId], [FName], [LName], [Type], [SubType]) VALUES (2, N'b', N'bb', 1, N'S12b')
INSERT [TableName] ([eId], [FName], [LName], [Type], [SubType]) VALUES (2, N'b', N'bb', 3, N'S31b')
INSERT [TableName] ([eId], [FName], [LName], [Type], [SubType]) VALUES (2, N'b', N'bb', 3, N'S32b')

查询（使用PIVOT功能）

SELECT eid, 
       fname, 
       lname, 
       [1] AS SubType1, 
       [3] AS SubType2 

FROM   (SELECT eid, [type], Max(fname) AS FName, Max(lname) AS LName, 
               Stuff((SELECT '; ' + subtype 
                      FROM   tablename t2 
                      WHERE  t2.eid = t1.eid 
                             AND t2.[type] = t1.[type] 
                      FOR xml path('')), 1, 2, '') AS SubType 
        FROM   tablename t1 
        GROUP  BY eid, [type]) sq 
       PIVOT ( Max(subtype) 
             FOR [type] IN ([1], [3]) ) piv 

产量

+-----+-------+-------+------------------+------------+
| eid | fname | lname |     SubType1     |  SubType2  |
+-----+-------+-------+------------------+------------+
|   1 | a     | aa    | S11a; S12a; S13a | S31a; S32a |
|   2 | b     | bb    | S11b; S12b       | S31b; S32b |
+-----+-------+-------+------------------+------------+

演示： http ： //www.sqlfiddle.com/#！18 / 1542b / 3/0