表变量和exec

Question

如何在执行命令字符串时使用表变量？

DECLARE @FileIDs TABLE 
(
   File_ID int
)
insert into @FileIDs select ID from Files where Name like '%bla%';

DECLARE @testquery as varchar(max);
set @testquery = 'select * from @FileIDs';
exec(@testquery);

返回以下错误

Msg 1087，Level 15，State 2，Line 1 必须声明表变量“@FileIDs”。

Answer 1

表格@FileIDs不在exec(@testquery)范围内。

这就是你遇到这个问题的原因。

---

要解决此问题，您可以使用temporary table：

CREATE table #FileIDs
(
   File_ID int
)
insert into #FileIDs select ID from Files where Name like '%bla%'; 

DECLARE @testquery as varchar(max);
set @testquery = 'select * from #FileIDs';
exec(@testquery);

drop table #FileIDs

或将表格放在范围内：

DECLARE @sql nvarchar(2000)

SET @sql='DECLARE @FileIDs TABLE (   File_ID int);'
SET @sql=@sql+'insert into @FileIDs select ID from Files where Name like ''%bla%'';'
set @sql=@sql+ 'select * from @FileIDs;'
EXECUTE sp_executesql @sql

Answer 2

确实表不在范围内，试试这个：

DECLARE @sql nvarchar(2000)

SET @sql='DECLARE @FileIDs TABLE (   File_ID int);'
SET @sql=@sql+'insert into @FileIDs select ID from Files where Name like ''%bla%'';'
set @sql=@sql+ 'select * from @FileIDs;'
EXECUTE sp_executesql @sql

Answer 3

 CREATE table #FileIDs
(
   File_ID int
)
insert into #FileIDs select ID from Files where Name like '%bla%'; 

DECLARE @testquery as varchar(max);
set @testquery = 'select * from #FileIDs';
exec(@testquery);

drop table #FileIDs