根据WHERE子句抑制SELECT输出

Question

我在这里有一个查询,在整个数据库中搜索我选择的特定GUID.现在,它正在完成它的编程操作:遍历所有列/表组合并输出可能包含或不包含信息的表.我想将此更改为仅输出包含结果的表.

这是代码:

DECLARE 
    @tab_list NVARCHAR(MAX),
    @col_list NVARCHAR(MAX),
    @IDquery NVARCHAR(MAX),
    @srvName NVARCHAR(MAX),
    @getList CURSOR

SET @srvName = 'Server_Name'

SET @getList = CURSOR LOCAL FAST_FORWARD FOR
    SELECT [TABLE_NAME]
        ,[COLUMN_NAME]
    FROM [Server_Name].[INFORMATION_SCHEMA].[COLUMNS]
    WHERE [COLUMN_NAME] LIKE '%id'
        AND [DATA_TYPE] LIKE 'uniqueidentifier'
    ORDER BY [TABLE_NAME] ASC

OPEN @getList

FETCH NEXT FROM @getList INTO @tab_list, @col_list

WHILE (@@FETCH_STATUS = 0)
BEGIN       
    PRINT @tab_list + ' -- ' + @col_list

    SET @IDquery = 
        'SELECT *' + 
        ' FROM ' + @srvName + '.dbo.' + @tab_list + 
        ' WHERE ' + @col_list + ' = (''GUID_HERE'')' +
        ' AND ' + @col_list + ' IS NOT NULL'

    --PRINT @IDquery
    EXEC (@IDquery)
    FETCH NEXT FROM @getList INTO @tab_list, @col_list
END

CLOSE @getList
DEALLOCATE @getList

它现在确实做到了,但效率却非常低.正如我之前提到的,当它搜索此GUID时,它会输出它搜索的任何表,甚至是那些没有匹配的表.我希望它只输出包含匹配的表,我不在乎如何.老实说,我甚至不关心它返回的是一个表和列,该东西找到匹配(意味着我必须手动命中该表).我只想要更清洁的输出,似乎无法将答案放在一起.

编辑:所以我喜欢临时表提供的承诺,虽然我遇到了一些障碍.这就是我所拥有的:

WHILE (@@FETCH_STATUS = 0)
    BEGIN       
        PRINT @tab_list + ' -- ' + @col_list

        SET @IDquery = 
            'SELECT * INTO #temporary' + 
            ' FROM ' + @srvName + '.dbo.' + @tab_list + 
            ' WHERE ' + @col_list + ' = (''GUID_HERE'')' +
            ' AND ' + @col_list + ' IS NOT NULL'

        --PRINT @IDquery
        EXEC (@IDquery)
        FETCH NEXT FROM @getList INTO @tab_list, @col_list
    END

IF (@@ROWCOUNT > 0)
SELECT @ FROM #temporary

DROP DATABASE #temporary
CLOSE @getList
DEALLOCATE @getList

我可能会错误地了解临时表的工作原理,但我看到没有使用此代码的表输出.

Answer 1

而不是直接从表中选择,而是将结果插入临时表.然后检查@@ROWCOUNT以确定是否找到了任何记录SELECT... INTO,如果是,则从临时表中选择结果:

SET @IDquery = '
    SELECT * INTO #Temp
    FROM ' + @srvName + '.dbo.' + @tab_list + ' 
    WHERE ' + @col_list + ' = (''GUID_HERE'')
    AND ' + @col_list + ' IS NOT NULL

    IF (@@ROWCOUNT > 0)
        SELECT * FROM #Temp
'

--PRINT @IDquery
EXEC (@IDquery)

FETCH NEXT FROM @getList INTO @tab_list, @col_list