在使用案例的Where子句中使用参数化列

Question

I am building a report in SSRS where I need to be able to let our users filter on different date fields. They need to be able to select the date filter and then the start and end dates within that filter.

This is a simplified Example of what I am trying to achieve:

SELECT Project.ProjectID, Project.Name, Project.Update_Date, Project.Due_Date, Project.Start_Date, Project.Review_Date
FROM Project
WHERE @datetypefiler BETWEEN @startdate AND @enddate

Where the @datetypefiler will essentially equal the field the user wishes to filter on (ie Project.Update_Date or Project.Due_Date etc)

On SSRS i built parameters for @datetypefiler which could equal the various date fields and I set up the start date and end date filter as expected.

Unfortunately it does not seem as though I can parameterize the @datetypefiler in this way? I then attempted to use the Case keyword as so:

SELECT Project.ProjectID, Project.Name, Project.Update_Date, Project.Due_Date, Project.Start_Date, Project.Review_Date
FROM Project
WHERE CASE 
when @datetypefiler='Project.Update_Date' then Project.Update_Date BETWEEN @startdate AND @enddate
when @datetypefiler='Project.Due_Date' then Project.Due_Date BETWEEN @startdate AND @enddate

This isnt working for me either, I figure that instead of taking shots in the dark I should ask what the correct method would look like. Any advice on this would be greatly appreciated,

Answer 1

You could try something like this:

SELECT * 
FROM Project
WHERE  (@datetypefiler='Project.Update_Date' 
                    AND Project.Update_Date BETWEEN @startdate AND @enddate)
    OR (@datetypefiler='Project.Due_Date' 
                    AND Project.Due_Date BETWEEN @startdate AND @enddate)

The OR will only evaluate the full statement if the @datetypefiler is matched.

Answer 2

Or you could try this

SELECT Project.ProjectID, Project.Name, Project.Update_Date, Project.Due_Date, 
Project.Start_Date, Project.Review_Date 
FROM Project
where 
(CASE 
when @datetypefiler = 'Project.Update_Date' then Project.Update_Date 
when @datetypefiler= 'Project.Due_Date' then Project.Due_Date 
END) BETWEEN @startdate AND @enddate

Answer 3

While both of other two answers are going to work just fine, they won't make use of index. I'd recommend to have two separate SELECT statements with two different queries based on your criteria, this way you can index your table both on Update_Date and Due_Date and actually use them to speed your queries up.