Question

我有接收性别价值的商店程序，可能是男性，女性或两者，我需要能够调整我的where子句，以便如果@gender值是'both'，那么select应该返回男性和女性，但如果性别是男性或女性，则应选择@gender值。我试过下面的查询，它给出了错误的语法错误。

选择 FirstName，SecondName，Gender，race，Height，HeightUnit，Weight，WeightUnit，EmailAdd 来自志愿者

IF @gender = 'both'
BEGIN

    WHERE Gender = 'male' or Gender ='female' 

END ELSE BEGIN

    WHERE Gender = @gender
END

Answer 1

您不能使用if来生成条件where子句。相反，只需将逻辑放在查询中：

基于OP，您需要：

select FirstName, SecondName, Gender, race, Height, HeightUnit,
       Weight, WeightUnit, EmailAdd
from volunteers
where @gender = 'both' and gender in ('male', 'female') or
      gender = @gender;

或者，这可能就足够了：

select FirstName, SecondName, Gender, race, Height, HeightUnit,
       Weight, WeightUnit, EmailAdd
from volunteers
where @gender = 'both' or
      gender = @gender;

Answer 2

好的如果我理解正确的话......试试这个：

select FirstName,SecondName,
CASE When @Gender = 'both' then 'Male, Female' else @Gender as Gender  END
,race,Height,HeightUnit, Weight,WeightUnit,EmailAdd from volunteers

你可以准确地调整你想说的内容，但这就是想法

更新：根据评论，这是他正在使用的完整程序：

    Create PROCEDURE spSelectUpdateTrial 

    @gender nvarchar(50), 
    @minage nvarchar(150), 
    @maxage nvarchar(150), 
    @country nvarchar(50), 
    @smoking nvarchar (50), 
    @smoke nvarchar(50), 
    @nct nvarchar(50) AS 

    select FirstName,
SecondName,
CASE 
When @Gender = 'both' 
then 'Male, Female' 
else @Gender
END 
as 
Gender,
race,
Height,
HeightUnit,
Weight,
WeightUnit,
EmailAdd 
from volunteers

注意我在else @gender

之后添加了END

sql server使用if else条件的地方

2 个答案: