Mysql 在串联列中与ms sql中的表不同

我在数据库中运行此查询，结果不明显。在select子句中使用连接时，是否有任何解决方案可以获得不同的结果

select
    case 
        when c.SubtypeId_FK is null then c.TypeDescription 
        else c.TypeDescription + ' In ' + cs.Subtype 
    end as Experties
from 
    CaseTLS c, 
    CaseLawyer cl , 
    Lawyer l , 
    CaseSubtype cs
where
    c.CaseId = cl.CaseID  
    and cl.ComputerCode = l.ComputerCode 
    and l.ComputerCode = @p1 
    and (
        c.SubtypeId_FK = cs.SubtypeId or c.SubtypeId_FK is null
    )

试试这个：

select
     DISTINCT case 
        when c.SubtypeId_FK is null then c.TypeDescription 
        else c.TypeDescription + ' In ' + cs.Subtype 
    end as Experties
from 
    CaseTLS c, 
    CaseLawyer cl , 
    Lawyer l , 
    CaseSubtype cs
where
    c.CaseId = cl.CaseID  
    and cl.ComputerCode = l.ComputerCode 
    and l.ComputerCode = @p1 
    and (
        c.SubtypeId_FK = cs.SubtypeId or c.SubtypeId_FK is null
    )

---

只需在select子句中使用Distinct。

使用

select Distinct case..

。如果可能，添加样本数据和预期输出，这将帮助您获得正确答案。

select
    case 
        when c.SubtypeId_FK is null then c.TypeDescription 
        else c.TypeDescription + ' In ' + cs.Subtype 
    end as Experties
from 
    CaseTLS c, 
    CaseLawyer cl , 
    Lawyer l , 
    CaseSubtype cs
where
    c.CaseId = cl.CaseID  
    and cl.ComputerCode = l.ComputerCode 
    and l.ComputerCode = @p1 
    and (
        c.SubtypeId_FK = cs.SubtypeId or c.SubtypeId_FK is null
    )