sql-server - SQL Server中的Case语句中的语法错误

Question

我在以下代码中收到语法错误:
我在所有出错的地方都加粗了。我可以使用if-else语句，但是我确实想要用例语句。
请帮我解决错误。

**CASE** @policy_type

        WHEN 'car' THEN 
        (Select policy_id,customer_id,policy_duration,requested_policy_amount,Car_Age
          ,Car_Amount
          ,Number_of_Accidents,estimated_car_premium INTO
           #PendingRequest FROM [dbo].[Policy] p join [dbo].[Car_Insurance] c on
          p.policy_type_id=c.policy_type_id and p.approved_policy_amount is Null 
          --And employee_id=@employee_id
          join
          [dbo].[Car_Insurance_Estimate] c_est on car_age >= c_est.min_car_age and car_age <= c_est.max_car_age
          and Car_Amount>=c_est.min_car_amount and Car_Amount<=c_est.max_car_amount and Number_of_Accidents>=c_est.min_accidents 
            and Number_of_Accidents<=c_est.max_accidents)

        **WHEN** 'life' THEN 

        (Select policy_id,customer_id,policy_duration,requested_policy_amount,Age
          ,l.Illness
          ,l.Income
          ,premium_insurance_percentage,amount_insurance_percentage
           INTO
           #PendingRequest from [dbo].[Policy] p join [dbo].[life_Insurance] l on
          p.policy_type_id=l.policy_type_id and p.approved_policy_amount is Null 
          And employee_id=@employee_id
          join
          [dbo].[life_Insurance_Estimate] l_est on age >= l_est.min_age and age <= l_est.max_age
          and income>=l_est.min_income and income<=l_est.max_income and l.illness=l_est.illness)

        when 'home' then 

        (Select policy_id,customer_id,policy_duration,requested_policy_amount,home_Age
          ,home_Amount
          ,h.Area,home_premium_percentage  INTO
           #PendingRequest 
          from [dbo].[Policy] p join [dbo].[home_Insurance] h on
          p.policy_type_id=h.policy_type_id and p.approved_policy_amount is Null 
          And employee_id=@employee_id
          join
          [dbo].[home_Insurance_Estimate] h_est on home_age >= h_est.min_home_age and home_age <= h_est.max_home_age
          and home_Amount>=h_est.min_home_amount and home_Amount<=h_est.max_home_amount and h.Area=h_est.area)


        **END**

Answer 1

在这种情况下，使用IF ... ELSE会容易得多。但是，如果您坚持使用CASE，那么这可能是一种选择:

DECLARE @SQL varchar(max);
SELECT @SQL=
CASE @policy_type

        WHEN 'car' THEN 
        'Select policy_id,customer_id,policy_duration,requested_policy_amount,Car_Age
          ,Car_Amount
          ,Number_of_Accidents,estimated_car_premium INTO
           #PendingRequest FROM [dbo].[Policy] p join [dbo].[Car_Insurance] c on
          p.policy_type_id=c.policy_type_id and p.approved_policy_amount is Null 
          --And employee_id=@employee_id
          join
          [dbo].[Car_Insurance_Estimate] c_est on car_age >= c_est.min_car_age and car_age <= c_est.max_car_age
          and Car_Amount>=c_est.min_car_amount and Car_Amount<=c_est.max_car_amount and Number_of_Accidents>=c_est.min_accidents 
            and Number_of_Accidents<=c_est.max_accidents'

        WHEN 'life' THEN 

        'Select policy_id,customer_id,policy_duration,requested_policy_amount,Age
          ,l.Illness
          ,l.Income
          ,premium_insurance_percentage,amount_insurance_percentage
           INTO
           #PendingRequest from [dbo].[Policy] p join [dbo].[life_Insurance] l on
          p.policy_type_id=l.policy_type_id and p.approved_policy_amount is Null 
          And employee_id=@employee_id
          join
          [dbo].[life_Insurance_Estimate] l_est on age >= l_est.min_age and age <= l_est.max_age
          and income>=l_est.min_income and income<=l_est.max_income and l.illness=l_est.illness'

        WHEN 'home' THEN 

        'Select policy_id,customer_id,policy_duration,requested_policy_amount,home_Age
          ,home_Amount
          ,h.Area,home_premium_percentage  INTO
           #PendingRequest 
          from [dbo].[Policy] p join [dbo].[home_Insurance] h on
          p.policy_type_id=h.policy_type_id and p.approved_policy_amount is Null 
          And employee_id=@employee_id
          join
          [dbo].[home_Insurance_Estimate] h_est on home_age >= h_est.min_home_age and home_age <= h_est.max_home_age
          and home_Amount>=h_est.min_home_amount and home_Amount<=h_est.max_home_amount and h.Area=h_est.area'

END

EXEC(@SQL);

拉吉