内连接语句，参数和where子句 [英] inner join statement, parameter and where clause

问题描述

我试图使用内部联接语句，参数和where 

子句来理解存储过程，但是当使用参数时没有任何反应。 我知道我可以在哪里兑换b $ color = red但我希望参数能够以不同的颜色传递我做错了什么？


exec  [dbo]。[spcolor]'blue'

exec  [dbo]。[spcolor]'red'





$
更改程序spcolor 

（

@color As varchar

）

AS

开始¥b $ b 选择 

  cn.namesofcars as nameofcars，

  c.color为颜色，

  st.seatmaterial

    FROM [blue]。[dbo]。[cartypes] as cn

 内连接[蓝色]。[dbo]。[颜色]为c on cn.colorid = c.colorid

 内联[蓝色]。[dbo]。[seattype] as st on cn.seatmaterialid = st.seatmaterialid

 其中c.color = @color

 结束

I am trying to understand stored procedures using an inner join statement, a parameter and a where 
clause, but when using a parameter nothing happens.  I know I can make the where 
statement c.color = red but I want the parameter to be able to pass in different colors what am i doing wrong

exec  [dbo].[spcolor] 'blue'
exec  [dbo].[spcolor] 'red'



ALTER PROCEDURE spcolor 
(
@color As varchar
)
AS
Begin
  select 
  cn.namesofcars as nameofcars,
  c.color as color,
  st.seatmaterial
   FROM [blue].[dbo].[cartypes] as cn
  inner join [blue].[dbo].[colors] as c On cn.colorid = c.colorid
  inner join [blue].[dbo].[seattype] as st On cn.seatmaterialid = st.seatmaterialid
  where c.color = @color
  End

推荐答案

ALTER PROCEDURE spcolor 

（

@color As varchar

）

AS

ALTER PROCEDURE spcolor 
(
@color As varchar
)
AS

好像你已经忘记了指定varchar参数的长度。在此上下文中，默认值为1，并且值已截断。尝试指定"@color varchar（30）" （或表格栏定义的最大长度）。

It seems you've forgotten to specify a length for the varchar parameter. The default is 1 in this context and the value truncated. Try specifying "@color varchar(30)" (or whatever the defined max length for table column).

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