SQL 如何通过连接检查合并来自链接服务器的选择

Question

我需要创建视图或过程，从 50 个链接服务器中选择一些数据，但其中一些可能处于脱机状态（网络状况不佳）。

我有这段代码

declare @srvr nvarchar(128), @retval int;
set @srvr = 'SERVER103';
begin try
    exec @retval = sys.sp_testlinkedserver @srvr;
end try
begin catch
    set @retval = sign(@@error);
end catch;
if @retval = 0
    select sel1.sum1, sel1.sum2, sel2.sum1, sel2.sum2 from
        (select sum(column1) as sum1, sum(column2) as sum2 from [SERVER103].[dbo].[table] where date like '201702%' group by column1, column2) as sel1
        (select sum(column1) as sum1, sum(column2) as sum2 from [SERVER103].[dbo].[table2] where date like '201702%' group by column1, column2) as sel2

但它仍然会引发有关连接的错误并破坏整个脚本。接下来我需要它必须通过所有链接的服务器并将结果合并为一个大结果。

有什么想法吗？谢谢

Answer 1

以下代码使用游标遍历每个链接服务器。如果连接良好，则添加动态 sql，否则会打印一条消息。结束动态 sql 只是为了好的链接：

declare @loop as int=1
declare @srvname as nvarchar(100)
declare @sql as nvarchar(max)=N''
declare @Date as varchar(10) = '201702%'
declare srvcursor cursor for select srvname from sysservers where srvname <> @@SERVERNAME
open srvcursor
fetch next from srvcursor into @srvname
WHILE @@FETCH_STATUS = 0
    begin
    begin try
    exec sys.sp_testlinkedserver @srvname
    set @sql=@sql+N'select sel1.sum1, sel1.sum2, sel2.sum1, sel2.sum2 from
        (select sum(column1) as sum1, sum(column2) as sum2 from [' + @srvname + N'].[dbo].[table] where date like ''' + @Date + N''' group by column1, column2) as sel1
        (select sum(column1) as sum1, sum(column2) as sum2 from [' + @srvname + N'].[dbo].[table2] where date like ''' + @Date + N''' group by column1, column2) as sel2
        UNION '
    end try
    begin catch
    print @srvname + 'is broken.'
    end catch
    fetch next from srvcursor into @srvname
    end
if @sql <> N''
    begin
    set @sql = left(@sql, len(@sql)-6)
    print @sql
    --exec(@sql)
    end
close srvcursor
deallocate srvcursor

SQL 如何通过连接检查合并来自链接服务器的选择

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