sp_MSforeachdb:仅包含具有结果的数据库的结果

Question

我sp_MSforeachdb用一个简单的命令运行下面的存储过程.我的问题是如何限制结果只显示至少有1条记录满足命令的数据库:

这是我的存储过程:

EXECUTE master.sys.sp_MSforeachdb 'USE [?]; 

IF (EXISTS (SELECT * 
                 FROM INFORMATION_SCHEMA.TABLES 
                 WHERE TABLE_NAME = ''Tabs''))
BEGIN

SELECT ''?'' as dbname,T.TabName, T.TabPath
FROM Tabs T
WHERE T.TabID IN (

SELECT Distinct TM.TabID
FROM TabModules TM
WHERE mID IN (
  ...
  )

)
ORDER BY T.TabName
END
'

任何想法我如何修改sp,以便它不显示具有空结果的数据库(见图)？

Answer 1

好吧,首先,停止使用sp_MSforEachDb.哦,问题(如果你想要证明,请看这里,这里和这里).

怎么样:

DECLARE @cmd NVARCHAR(MAX) = N'', @sql NVARCHAR(MAX) = N'';

SELECT @cmd += N'IF EXISTS (SELECT 1 FROM '
  + QUOTENAME(name) + '.sys.tables WHERE name = N''Tabs'')
  SET @sql += N''UNION ALL 
    SELECT ''''' + name + ''''',T.TabName
    FROM ' + QUOTENAME(name) + '.dbo.Tabs AS T
    WHERE EXISTS 
    (
      SELECT 1 FROM ' + QUOTENAME(name) + '.dbo.TabModules AS TM
        WHERE TM.TabID = T.TabID
        AND TM.mID IN -- this should probably be exists too
        ( 
          ...
        )
    )
'''
FROM sys.databases 
  WHERE state = 0 -- assume you only want online databases
  AND database_id > 4; -- assume you don't want system dbs

EXEC sp_executesql @cmd, N'@sql NVARCHAR(MAX) OUTPUT', @sql OUTPUT;

SET @sql = STUFF(@sql, 1, 10, '') + N' ORDER BY TabName;';   

PRINT @sql; -- this will appear truncated, but trust me, it is not truncated
-- EXEC sp_executesql @sql;

如果您确实需要一些未知的,任意数量的单独结果集,则更改很简单.

DECLARE @cmd NVARCHAR(MAX) = N'', @sql NVARCHAR(MAX) = N'';

SELECT @cmd += N'IF EXISTS (SELECT 1 FROM '
  + QUOTENAME(name) + '.sys.tables WHERE name = N''Tabs'')
  SET @sql += N''SELECT ''''' + name + ''''',T.TabName
    FROM ' + QUOTENAME(name) + '.dbo.Tabs AS T
    WHERE EXISTS 
    (
      SELECT 1 FROM ' + QUOTENAME(name) + '.dbo.TabModules AS TM
        WHERE TM.TabID = T.TabID
        AND TM.mID IN -- this should probably be exists too
        ( 
          ...
        )
    )
 ORDER BY T.TabName;
 '';'
FROM sys.databases 
  WHERE state = 0 -- assume you only want online databases
  --AND database_id > 4; -- assume you don't want system dbs

EXEC sp_executesql @cmd, N'@sql NVARCHAR(MAX) OUTPUT', @sql OUTPUT;

PRINT @sql; -- this will appear truncated, but trust me, it is not truncated
-- EXEC sp_executesql @sql;