将参数传递给存储过程时为什么会出错？

Question

我已经创建了一个存储过程来将IP地址拆分为四个不同的列.

ALTER PROCEDURE ipaddress_split
(
    @str as varchar(max)
)
AS 
BEGIN
    SET NOCOUNT ON

    DECLARE @query as varchar(max)  
    SET  @query = 'SELECT   parsename('+@str+',4) as A
                        ,   parsename('+@str+',3) as B
                        ,   parsename('+@str+',2) as C
                        ,   parsename('+@str+',1) as D';
    EXEC (@query)
    SET NOCOUNT off
END

但是,当我传递参数时,我收到错误.

EXEC ipaddress_split @str='191.168.1.1'

Msg 102, Level 15, State 1, Line 1
Incorrect syntax near '.1'.

我尝试了下面提到的所有组合但没有成功.

exec ipaddress_split '191.168.1.1'
exec ipaddress_split 191.168.1.1
exec ipaddress_split ('191.168.1.1')

将参数传递给存储过程的正确方法是什么？

Answer 1

您不必动态生成查询以拆分IP地址输入.你可以做这样的事情.

存储过程脚本:

ALTER PROCEDURE ipaddress_split
(
    @str AS VARCHAR(max)
)
AS  
BEGIN

SET NOCOUNT ON

SELECT  PARSENAME(@str, 4) AS A
    ,   PARSENAME(@str, 2) AS B
    ,   PARSENAME(@str, 3) AS C
    ,   PARSENAME(@str, 1) AS D

SET NOCOUNT OFF

END;

执行声明:

EXEC ipaddress_split @str = '191.168.1.1';

输出:

A   B   C   D
--- --- --- ---
191 1   168 1

您的问题原因:

您的动态查询的计算结果如下.它不会将PARSENAME函数的输入视为字符串.

SELECT parsename(191.168.1.1,4) as A,parsename(191.168.1.1,3) 
as B,parsename(191.168.1.1,2) as C,parsename(191.168.1.1,1) as D

您必须通过在查询中显示的每个单引号包含两个额外的单引号来将set query语句更改为这样.

set @query = 'SELECT parsename('''+@str+''',4) as A,parsename('''+@str+''',3) 
as B,parsename('''+@str+''',2) as C,parsename('''+@str+''',1) as D';

您的动态查询将变为这样

SELECT parsename('191.168.1.1',4) as A,parsename('191.168.1.1',3) as
B,parsename('191.168.1.1',2) as C,parsename('191.168.1.1',1) as D

无论如何,我不建议你这样做.这不是正确的做法.