测试链接服务器中是否存在表(服务器名称是参数)

Question

我需要测试一个表是否存在于链接服务器中,其中链接服务器是一个参数(必须是),这就是我使用exec方法的原因.我尝试了很多方法,但没有成功.

Declare @LinkedServerName varchar(50)
Declare @DS varchar(50)
Declare @username varchar(50)
Declare @pswd varchar(12)
Declare @TableExists int

Set @DS = 'test\TestDB'
Set @LinkedServerName = 'LinkedServerAutoAddDrop'
Set @username = 'ua'
Set @pswd = 'pass'
Set @TableExists = 0

if not exists(select * from sys.servers where name = @LinkedServerName)
BEGIN
    EXEC sp_addlinkedserver   
       @server=@LinkedServerName, 
       @srvproduct='',
       @provider='SQLNCLI', 
       @datasrc=@DS

    EXEC sp_addlinkedsrvlogin @LinkedServerName, N'false', NULL, @username, @pswd
    exec sp_serveroption @server=@LinkedServerName, @optname='rpc', @optvalue='TRUE'
    exec sp_serveroption @server=@LinkedServerName, @optname='rpc out', @optvalue='TRUE'
END


exec('IF (EXISTS (SELECT * FROM OPENQUERY([' + @LinkedServerName + '], ''select * from LinkedDB.INFORMATION_SCHEMA.TABLES Where TABLE_NAME = ''''TableName'''''')))
BEGIN
    exec (''Set ' + @TableExists + ' = 1'')

END')

IF (@TableExists = 1)
BEGIN
    exec('Insert Into ...')
END

Answer 1

我个人会使用sp_executesql输出参数:

DECLARE @SQL NVARCHAR(MAX) = ''
DECLARE @TableExists BIT;

SET @SQL = 'SELECT @TableExists = CASE WHEN TableExists = 0 THEN 0 ELSE 1 END
            FROM OPENQUERY(' + QUOTENAME(@LinkedServerName) 
            + ', ''SELECT TableExists = COUNT(*) 
                    FROM LinkedDB.INFORMATION_SCHEMA.TABLES
                    WHERE TABLE_NAME = ''''TableName'''''');';

EXECUTE sp_executesql @SQL, N'@TableExists BIT OUTPUT', @TableExists OUT;

IF (@TableExists = 1)
BEGIN
    -- DO SOMETHING
END;