无效的列名，来自C＃的参数

Question

select  (ABS(MAX((convert(int,WIDTH))- (convert(int,HEIGHT))))) as parameter ,LAYOUT,FORM_NAMESPACE_NAME from [FORM_LAYOUT]

group by  WIDTH,HEIGHT,LAYOUT,FORM_NAMESPACE_NAME

order by ABS(MAX((convert(int,WIDTH))- (convert(int,HEIGHT)))) desc

this works like that.

but i want to put a parameter. i will send this parameter in my program (c#) .

let's say i put my parameter 500, so it must work like

(ABS(MAX((convert(int,WIDTH))- (convert(int,HEIGHT))))) as parameter<500

in order to achieve that

select  (ABS(MAX((convert(int,WIDTH))- (convert(int,HEIGHT))))) as parameter ,LAYOUT,FORM_NAMESPACE_NAME from [FORM_LAYOUT]

where parameter <500
group by  WIDTH,HEIGHT,LAYOUT,FORM_NAMESPACE_NAME

order by ABS(MAX((convert(int,WIDTH))- (convert(int,HEIGHT)))) desc

doesn't work. It says "invalid column name parameter"

how can i correct it.

Thanks.

Answer 1

Query should be

select  (ABS(MAX((convert(int,WIDTH))- (convert(int,HEIGHT))))) as parameter ,LAYOUT,FORM_NAMESPACE_NAME from [FORM_LAYOUT] 
group by  WIDTH,HEIGHT,LAYOUT,FORM_NAMESPACE_NAME
having ABS(MAX((convert(int,WIDTH))- (convert(int,HEIGHT)))) < 500    
order by ABS(MAX((convert(int,WIDTH))- (convert(int,HEIGHT)))) desc

Answer 2

You can accomplish this in two ways.

1) change your where statement to the following

WHERE (ABS(MAX((convert(int,WIDTH))- (convert(int,HEIGHT))))) < 500
GROUP BY LAYOUT, FORM_NAMESPACE_NAM

2) Use a sub query

SELECT [parameter]
FROM (SELECT (ABS(MAX((convert(int,WIDTH))- (convert(int,HEIGHT))))) as [parameter])
WHERE parameter < 500