Question

我在下面有这个查询。但我认为有更好的方式来写这个。两者之间的唯一区别是VacancyType检查

IF @VacancyType = '' 
        SELECT COUNT(a.[ApplicationID]) [AppCount], YEAR(a.[DateCreated]) [Year], MONTH(a.[DateCreated]) [Month]
        FROM [Application] a
        INNER JOIN [Vacancy] v ON v.VacancyID = a.VacancyID
        INNER JOIN Staff s ON s.StaffID = v.StaffID

        WHERE 
        v.[DateCreated] >= @DateFrom AND v.[DateCreated] <= @DateTo 
        AND (@OfficeID = 0 Or s.OfficeID = @OfficeID)
        AND v.VacancyType IN (SELECT TypeID FROM VacancyType) 

        GROUP BY YEAR(a.[DateCreated]), MONTH(a.[DateCreated])
        ORDER BY YEAR(a.[DateCreated]), MONTH(a.[DateCreated])

    ELSE 
        SELECT COUNT(a.[ApplicationID]) [AppCount], YEAR(a.[DateCreated]) [Year], MONTH(a.[DateCreated]) [Month]
        FROM [Application] a
        INNER JOIN [Vacancy] v ON v.VacancyID = a.VacancyID
        INNER JOIN Staff s ON s.StaffID = v.StaffID

        WHERE 
        v.[DateCreated] >= @DateFrom AND v.[DateCreated] <= @DateTo 
        AND (@OfficeID = 0 Or s.OfficeID = @OfficeID)
        AND v.VacancyType = @VacancyType

        GROUP BY YEAR(a.[DateCreated]), MONTH(a.[DateCreated])
        ORDER BY YEAR(a.[DateCreated]), MONTH(a.[DateCreated])

Answer 1

假设唯一区别在于v.VacancyType条件，那么您可以使用OR

    SELECT COUNT(a.[ApplicationID]) [AppCount], YEAR(a.[DateCreated]) [Year], MONTH(a.[DateCreated]) [Month]
    FROM [Application] a
    INNER JOIN [Vacancy] v ON v.VacancyID = a.VacancyID
    INNER JOIN Staff s ON s.StaffID = v.StaffID

    WHERE 
    v.[DateCreated] >= @DateFrom AND v.[DateCreated] <= @DateTo 
    AND (@OfficeID = 0 Or s.OfficeID = @OfficeID)
    AND 
    (
       (@VacancyType = '' AND v.VacancyType IN (SELECT TypeID FROM VacancyType)) OR
       (@VacancyType <> '' AND v.VacancyType = @VacancyType)
    )
    GROUP BY YEAR(a.[DateCreated]), MONTH(a.[DateCreated])
    ORDER BY YEAR(a.[DateCreated]), MONTH(a.[DateCreated])

Answer 2

试试这个

SELECT COUNT(a.[ApplicationID]) [AppCount], YEAR(a.[DateCreated]) [Year], MONTH(a.[DateCreated]) [Month]
FROM [Application] a
INNER JOIN [Vacancy] v ON v.VacancyID = a.VacancyID
INNER JOIN Staff s ON s.StaffID = v.StaffID

WHERE 
v.[DateCreated] >= @DateFrom AND v.[DateCreated] <= @DateTo 
AND (@OfficeID = 0 Or s.OfficeID = @OfficeID)
AND ((@VacancyType = '' AND v.VacancyType IN (SELECT TypeID FROM VacancyType)) 
  OR (v.VacancyType = @VacancyType)
)

GROUP BY YEAR(a.[DateCreated]), MONTH(a.[DateCreated])
ORDER BY YEAR(a.[DateCreated]), MONTH(a.[DateCreated])

有没有更好的方法来写这个

2 个答案: