存储过程在While循环中选择语句

Question

我想在While循环中执行我的选择查询，但它不起作用。

Set @i = 1 
    While(@i <= @rowNumber) 

    BEGIN 

     Set @q_getoldeMail = 'SELECT Lower('+@columnname+') FROM (
     SELECT ROW_NUMBER() OVER (ORDER BY ID) AS rownumber 
      ,ID 
      ,[Name] 
      ,[Description] 
      ,[Status] 
      ,[AssignedTo] 
      ,[AssignedToMail] 
      ,[CC] 
     FROM ' + QUOTENAME(@tablename) + ') AS ar Where rownumber = '+@i+'' 

    exec sp_executesql @q_getoldeMail, N'@get_oldeMail nvarchar(100) output', @get_oldeMail output 

     Set @i = @i+1 

在其他方面，我想没有while循环是这样执行的查询：

Set @q_getoldeMail = 'SELECT Lower('+@columnname+') FROM (
      SELECT ROW_NUMBER() OVER (ORDER BY ID) AS rownumber 
       ,ID 
       ,[Name] 
       ,[Description] 
       ,[Status] 
       ,[AssignedTo] 
       ,[AssignedToMail] 
       ,[CC] 
      FROM ' + QUOTENAME(@tablename) + ') AS ar Where rownumber = '+@i+'' 

     exec sp_executesql @q_getoldeMail, N'@get_oldeMail nvarchar(100) output', @get_oldeMail output 

它不工作，要么。我的错误是什么？有没有一种方法从While循环获得Select语句的值？你可以帮我吗？

编辑：

我在此代码部分设置@RowCount值：

SET @q_getrowNumber = 'SELECT Count(ID) 
FROM dbo.' + quotename(@tablename) + '' 

execute sp_executesql @q_getrowNumber, N'@rownumber int output', @rownumber output 

该代码部分返回一个值（112）。但是，当我改变@罗斯卡尔

Set @rowcount = 2 

然后代码工作。我想转换成整数@RowCount，但它没有工作

Answer 1

可能这是你在找什么 - “它不工作”

declare @i int = 1 
declare @rownumber int = 2 
declare @result_set table (value varchar(1000)) 
declare @q_getoldeMail nvarchar(max) 
declare @columnname varchar(100) = 'name' 
declare @tablename varchar(100) = 'sys.columns' 
--select * from sys.columns 

Set @i = 1 
While(@i <= @rowNumber) 
BEGIN 
    Set @q_getoldeMail = 'SELECT Lower('+@columnname+') FROM (
    SELECT ROW_NUMBER() OVER (ORDER BY object_ID) AS rownumber 
     ,object_id 
     ,name 
    FROM ' + (@tablename) + ') AS ar Where rownumber = '+convert(varchar,@i)+'' 

    insert into @result_set 
    exec sp_executesql @q_getoldeMail 

    Set @i = @i+1 
end 

select * from @result_set