sql - 关于存储过程中的情况

Question

我有以下查询。

 declare @Prm_CourseId int
declare @Prm_SpecializationId int
set @Prm_CourseId=5
set @Prm_SpecializationId=0
declare @WhrStr varchar(500)


set @WhrStr =  case @Prm_CourseId
                when 0 then
                    'e.CourseId is null or e.CourseId is not  null'
                when -1 then
                    'e.CourseId is null or e.CourseId is not  null'
                when isnull(@Prm_CourseId,0)  then
                     'e.CourseId is null or e.CourseId is not  null'
                else
                     'e.CourseId= '+Convert(varchar,@Prm_CourseId)

                 end
set @WhrStr  = case @Prm_SpecializationId
                when 0 then
                    'e.SpecializationId is null or e.SpecializationId is not  null'
                when -1 then
                    'e.SpecializationId is null or e.SpecializationId is not  null'
                when isnull(@Prm_SpecializationId,0)  then
                     'e.SpecializationId is null or e.SpecializationId is not  null'
                else
                     'e.SpecializationId= '+Convert(varchar,@ Prm_SpecializationId)
                end
print @WhrStr
    exec(
            'select f.EnquiryID,
            e.[Name],
            f.AttendedBy,
            f.Remarks,
            f.CreatedDate
            from STD_FollowUp f
                inner join
                    STD_Enquiry e
                     on f.EnquiryId=e.EnquiryId
            where'+' '+@WhrStr
    )

这里的问题是我想在@WhrStr 中获得第一个和第二个 case 语句的结果。但是 WhrStr 中的值是'e.SpecializationId 为空或 e.SpecializationId 不为空'意味着第一个被第二个覆盖。无论如何将第二个附加到第一个。

Answer 1

这在多个级别上都行不通。

• 您不能将字符串附加到查询中。它要么全是动态的，要么全都不是。

• CASE WHEN 位需要在字符串分隔符中"...THEN '(e.CourseId is null or e.CourseId is not null)'...

• “e.CourseId 为空或 e.CourseId 不为空”是一样的“总是给我数据”

所有你需要的是：

select f.EnquiryID,
    e.[Name],
    f.AttendedBy,
    f.Remarks,
    f.CreatedDate
from STD_FollowUp f
            inner join
                    STD_Enquiry e
                    on f.EnquiryId=e.EnquiryId

Answer 2

if (isnull(@Prm_CourseId, 0) = 0 or isnull(@Prm_CourseID, 0) = -1)
    set @Prm_CourseId = null

if (isnull(@Prm_SpecializationId, 0) = 0 or isnull(@Prm_SpecializationId, 0) = -1)
    set @Prm_SpecializationId = null

select f.EnquiryID,
e.[Name],
f.AttendedBy,
f.Remarks,
f.CreatedDate
from STD_FollowUp f
inner join
STD_Enquiry e
on f.EnquiryId=e.EnquiryId
where (@Prm_CourseId is null or e.CourseId = @Prm_CourseId)
or (@Prm_SpecializationId is null or e.SpecializationId = @Prm_SpecializationId)