如何设置局部变量值等于 CTE table 的结果？

Question

我有一个问题我们有这样的 table HR

EmpName    Empmanager
Jack        Jane
Tom         Jane 
Tony        Victor
Isabella    Hugo
Anna        Victor

所以我想逐行提取 DISTINCT emp.manager 然后 select 并将它们提供给变量假设 mgrname。我在 SET @mgrname 语法中遇到错误？

DECLARE @count INT
DECLARE @mgrname VARCHAR(20)
SET @count = 3
WITH  MGRlist as(
    SELECT DISTINCT Empmanager FROM HR)
    **SET @mgrname** = SELECT Empmanager  FROM (
    SELECT ROW_NUMBER() OVER (ORDER BY mgr ASC) AS RowNumber,
    *
    FROM MGRlist
    ) AS RESULT
    WHERE RowNumber = @count -- FIND THE CURRENT MANAGER NAME

Answer 1

select 'Jack'      as Empname ,  'Jane'   as empmanager
into #temp1  union all 
select 'Tom'       as Empname ,  'Jane'   as empmanager union all  
select 'Tony'      as Empname ,  'Victor' as empmanager union all 
select 'Isabella'  as Empname ,  'Hugo'   as empmanager union all 
select 'Anna'      as Empname ,  'Victor' as empmanager  


DECLARE @count INT
DECLARE @mgrname VARCHAR(20)
SET @count = 3

SELECT DISTINCT Empmanager into #temp2 FROM #temp1


set @mgrname =   (SELECT Empmanager  FROM (
SELECT ROW_NUMBER() OVER (ORDER BY empmanager ASC) AS RowNumber,
*
FROM #temp2
) AS RESULT
WHERE RowNumber = @count)  -- FIND THE CURRENT MANAGER NAME

select @mgrname as CurrentManagername

输出：

   CurrentManagername
    Victor

您可以创建一个临时 table 并使用它来引用，直到会话处于活动状态。

Answer 2

DECLARE @count INT
DECLARE @mgrname VARCHAR(20)
SET @count = 3
;WITH  MGRlist as(
    SELECT DISTINCT Empmanager FROM HR)
    SELECT @mgrname= Empmanager  FROM (
    SELECT ROW_NUMBER() OVER (ORDER BY Empmanager ASC) AS RowNumber,
    *
    FROM MGRlist
    ) AS RESULT
    WHERE RowNumber = @count

Answer 3

如果您想在这种情况下获得不同的经理姓名，则不需要 CTE。

您正在尝试在 VARCHAR 数据类型

中插入多个值

DECLARE @mgrname VARCHAR(20)

您应该创建一个 TABLE 类型的变量，而不是创建一个 VARCHAR 变量，它可以包含多个值，如下所示。

DECLARE @mgrname TABLE(ManagerName VARCHAR(100))

要获取特定数量的不同经理姓名，您可以使用

SELECT DISTINCT TOP (@count)

您的最终查询应如下所示。

DECLARE @count INT
DECLARE @mgrname table (ManagerName VARCHAR(100))
SET @count = 3

INSERT INTO @mgrname
SELECT DISTINCT TOP (@count)  Empmanager FROM HR
ORDER BY Empmanager
--Now output is stored inside a table variable.
SELECT * FROM @mgrname

如何设置局部变量值等于 CTE table 的结果？

How to SET the local variable value equal to result from CTE table?

sql

sql-server

tsqlt