我想 select 相同 Table 相同的列来分隔 Desc_Main 和 Desc_sup 通过 cdValuse

Question

我想从 cdValue

中分离到 Desc_Main 和 Desc_Sup

1. 100000 是主要的并且有来自 cdValue
的 sup 值是 '101000','102000'
2. 200000 是主要的并且有来自 cdValue
的 sup 值是 '201000','202000'

我想在这个table

中展示

我的脚本

 SELECT 
          cdValue
        , Desc_sup  =   CASE Left(cdValue,3)
                        WHEN '100' THEN cdDesc_th
                        WHEN '200' THEN cdDesc_th
                        ELSE cdDesc_th END 
        ,
         Desc_Main  =   CASE Left(cdValue,3)
                        WHEN '101' THEN cdDesc_th 
                        WHEN '102' THEN cdDesc_th
                        WHEN '103' THEN cdDesc_th
                        WHEN '104' THEN cdDesc_th
                        WHEN '105' THEN cdDesc_th
                        WHEN '106' THEN cdDesc_th
                        WHEN '201' THEN cdDesc_th
                        WHEN '202' THEN cdDesc_th
                        ELSE cdDesc_th END
        FROM SellingAgent..tb_LookupCode (NOLOCK) 
        WHERE cdType='Cat_FAQ'

请帮我使用Case-when 非常感谢

Answer 1

如果你的DBMS版本是2012+那么，可以使用first_value()函数

  with tb_LookupCode(cdValue, Desc_sup, Desc_Main) as
          (
           select 100000, 'FAQ','FAQ' union all
           select 101000, 'Philip Fund','Philip Fund' union all   
           select 102000, 'LTF&RMF','LTF&RMF' union all
           select 200000, 'Article','Article' union all
           select 201000, 'Financial Article','Financial Article'  
          )
   select first_value(cdValue) over 
          (partition by substring(cast(cdValue as varchar(25)),1,1) 
           order by cdValue)
          as cdValue,
          first_value(Desc_sup) over 
          (partition by substring(cast(cdValue as varchar(25)),1,1) 
           order by substring(cast (cdValue as varchar(25)),1,1))
          as Desc_sup,
          Desc_Main
     from tb_LookupCode l;

cdValue Desc_sup    Desc_Main
------- -------- ------------------ 
100000   FAQ          FAQ
100000   FAQ       Philip Fund
100000   FAQ        LTF&RMF
200000  Article     Article
200000  Article   Financial Article

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