一列保存多个ID(将多个用逗号隔开的ID转换成用逗号隔开的名称)

IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[Department]'))
DROP TABLE [dbo].Department
GO
--部门表
CREATE TABLE Department
(
id int,
name nvarchar(50)
)
INSERT INTO Department(id,name)
SELECT 1,'人事部'
UNION
SELECT 2,'工程部'
UNION
SELECT 3,'管理部'
SELECT * FROM Department

IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[Employee]'))
DROP TABLE [dbo].Employee
GO
--员工表
CREATE TABLE Employee
(
id int,
name nvarchar(20),
deptIds varchar(1000)
)
INSERT INTO Employee(id,name,deptIds)
SELECT 1,'蒋大华','1,2,3'
UNION
SELECT 2,'小明','1'
UNION
SELECT 3,'小华',''
SELECT * FROM Employee

SELECT E.*,ISNULL(D.name,'') AS deptName
FROM Employee AS E
OUTER APPLY dbo.fun_SplitIds(E.deptIds) AS DID
LEFT JOIN Department AS D ON DID.ID=D.id;

;WITH EmployeT AS(
--员工的基本信息(使用OUTER APPLY将多个ID拆分开来,然后与部门表相关联)
--此时已将员工表所存的IDS分别与部门相关联,下面需要将此集合中的deptName聚合成一个记录
SELECT E.*,ISNULL(D.name,'') AS deptName
FROM Employee AS E
OUTER APPLY dbo.fun_SplitIds(E.deptIds) AS DID
LEFT JOIN Department AS D ON DID.ID=D.id
),mike AS(
SELECT id,name,deptIds,deptName
,ROW_NUMBER()OVER(PARTITION BY id ORDER BY id) AS level_num
FROM EmployeT
),mike2 AS(
SELECT id,name,deptIds,CAST(deptName AS NVARCHAR(100)) AS deptName,level_num
FROM mike
WHERE level_num=1
UNION ALL
SELECT m.id,m.name,m.deptIds,CAST(m2.deptName+','+m.deptName AS NVARCHAR(100)) AS deptName,m.level_num
FROM mike AS m
INNER JOIN mike2 AS m2 ON m.ID=m2.id AND m.level_num=m2.level_num+1
),maxMikeByIDT AS(
SELECT id,MAX(level_num) AS level_num
FROM mike2
GROUP BY ID
)

SELECT A.id,A.name,A.deptIds,A.deptName
FROM mike2 AS A
INNER JOIN maxMikeByIDT AS B ON A.id=B.ID AND A.level_num=B.level_num
ORDER BY A.id OPTION (MAXRECURSION 0)

IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[Department]'))
DROP TABLE [dbo].Department
GO
--部门表
CREATE TABLE Department
(
id int,
name nvarchar(50)
)
INSERT INTO Department(id,name)
SELECT 1,'人事部'
UNION
SELECT 2,'工程部'
UNION
SELECT 3,'管理部'

SELECT * FROM Department


IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[Employee]'))
DROP TABLE [dbo].Employee
GO
--员工表
CREATE TABLE Employee
(
id int,
name nvarchar(20),
deptIds varchar(1000)
)
INSERT INTO Employee(id,name,deptIds)
SELECT 1,'蒋大华','1,2,3'
UNION
SELECT 2,'小明','1'
UNION
SELECT 3,'小华',''

SELECT * FROM Employee

--创建一个表值函数，用来拆分用逗号分割的数字串，返回只有一列数字的表
IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[fun_SplitIds]'))
DROP FUNCTION [dbo].fun_SplitIds
GO
CREATE FUNCTION dbo.fun_SplitIds(
@Ids nvarchar(1000)
)
RETURNS @t_id TABLE (id VARCHAR(36))
AS
BEGIN
DECLARE @i INT,@j INT,@l INT,@v VARCHAR(36);
SET @i = 0;
SET @j = 0;
SET @l = len(@Ids);
while(@j < @l)
begin
SET @j = charindex(',',@Ids,@i+1);
IF(@j = 0) set @j = @l+1;
SET @v = cast(SUBSTRING(@Ids,@i+1,@j-@i-1) as VARCHAR(36));
INSERT INTO @t_id VALUES(@v)
SET @i = @j;
END
RETURN;
END
GO


;WITH EmployeT AS(
--员工的基本信息(使用OUTER APPLY将多个ID拆分开来,然后与部门表相关联)
--此时已将员工表所存的IDS分别与部门相关联,下面需要将此集合中的deptName聚合成一个记录
SELECT E.*,ISNULL(D.name,'') AS deptName
FROM Employee AS E
OUTER APPLY dbo.fun_SplitIds(E.deptIds) AS DID
LEFT JOIN Department AS D ON DID.ID=D.id
),mike AS(
SELECT id,name,deptIds,deptName
,ROW_NUMBER()OVER(PARTITION BY id ORDER BY id) AS level_num
FROM EmployeT
),mike2 AS(
SELECT id,name,deptIds,CAST(deptName AS NVARCHAR(100)) AS deptName,level_num
FROM mike
WHERE level_num=1
UNION ALL
SELECT m.id,m.name,m.deptIds,CAST(m2.deptName+','+m.deptName AS NVARCHAR(100)) AS deptName,m.level_num
FROM mike AS m
INNER JOIN mike2 AS m2 ON m.ID=m2.id AND m.level_num=m2.level_num+1
),maxMikeByIDT AS(
SELECT id,MAX(level_num) AS level_num
FROM mike2
GROUP BY ID
)

SELECT A.id,A.name,A.deptIds,A.deptName
FROM mike2 AS A
INNER JOIN maxMikeByIDT AS B ON A.id=B.ID AND A.level_num=B.level_num
ORDER BY A.id OPTION (MAXRECURSION 0)