混淆引號和雙引號中查詢

Question

我有精美的作品查詢：

CREATE Procedure BCP_Text_File 
( 
    @table varchar(100), 
    @FileName varchar(100) 
) 
AS 
    If exists(Select * from information_Schema.tables where table_name=@table) 
    Begin 
     Declare @str varchar(1000) 
     set @str='Exec Master..xp_Cmdshell ''bcp "Select * from '+db_name()+'..'+@table+'" queryout "'+@FileName+'" -c''' 
     Exec(@str) 
    end 
    else 
     Select 'The table '+@table+' does not exist in the database' 

，但我需要在那裏補充一點：

select column_name 
from information_schema.columns 
where table_name = @table 
order by ordinal_position 

到目前爲止，我有：

alter Procedure BCP_Text_File 
    ( 
     @table varchar(100), 
     @FileName varchar(100) 
    ) 
    AS 
     If exists(Select * from information_Schema.tables where table_name=@table) 
     Begin 
      Declare @str varchar(1000) 
      set @str='Exec Master..xp_Cmdshell ''bcp " 

      select column_name 
      from information_schema.columns 
      where table_name = '+db_name()+'..'+@table+' 
      order by ordinal_position 

      Select * from '+db_name()+'..'+@table+'" queryout "'+@FileName+'" -c''' 
      Exec(@str) 
     end 
     else 
      Select 'The table '+@table+' does not exist in the database' 

但我想我錯過了單引號和/或雙引號。我將添加此選擇語句，以便我的結果將字段名稱作爲第一行。

非常感謝您的幫助或指導。

Answer 1

也許這就是你想要的？這假設（a）列名中沒有逗號，並且（b）每列的輸出在隱式轉換爲字符串時都可以。

ALTER PROCEDURE dbo.BCP_Text_File 
    @table NVARCHAR(255), 
    @filename VARCHAR(100) 
AS 
BEGIN 
    SET NOCOUNT ON; 

    IF OBJECT_ID(@table) IS NOT NULL 
    BEGIN 
    DECLARE 
     @sql NVARCHAR(MAX), 
     @cols NVARCHAR(MAX) = N''; 

    SELECT @cols += ',' + name 
     FROM sys.columns 
     WHERE [object_id] = OBJECT_ID(@table) 
     ORDER BY column_id; 

    SELECT @cols = STUFF(@cols, 1, 1, ''); 

    SET @sql = N'EXEC master..xp_cmdshell ''bcp "SELECT ''''' 
     + REPLACE(@cols, ',', ''''',''''') + ''''' UNION ALL SELECT ' 
     + 'RTRIM(' + REPLACE(@cols, ',', '),RTRIM(') + ') FROM ' 
     + DB_NAME() + '..' + @table + '" queryout "' + @filename + '" -c'''; 

    EXEC sp_executesql @sql; 
    END 
    ELSE 
    BEGIN 
    SELECT 'The table '+@table+' does not exist in the database'; 
    END 
END 
GO 

但我必須同意你從其他人那裏得到的關於這個和其他問題的建議 - 這種方法非常脆弱。你正試圖用壓路機打開開心果。

PS我刪除了引用INFORMATION_SCHEMA，因爲我認爲the catalog views are more reliable and more consistent。