小白菜求助，SQL限制条件优化

最近遇到了一个个人觉得比较变态的限制条件，严重影响执行速度，个人技能有限，还没法对他进行优化，跪求高人指点，代码如下

1. SELECT
   
2.   '补充' AS dataclass
   
3. , blart
   
4. , budat
   
5. , budat_1
   
6. ,xblnr
   
7. , mblnr
   
8. , mjahr
   
9. , zeile
   
10. , bwart
    
11. , sku
    
12. ,CASE WHEN bwart IN ('641','642') AND sobkz = 'K' THEN ltrim (umwrk,'0')
    
13. ELSE  ltrim (werks,'0') END AS werks
    
14. ,CASE when (bwart in ('102','101','305','306','Z07','Z08'))
    
15. THEN '' ELSE lgort END  AS lgort
    
16. --, a.werks
    
17.   --, a.lgort
    
18.   , charg
    
19.   , sobkz
    
20.   , lifnr
    
21.   , shkzg
    
22.   , kokrs
    
23.   , gjahr
    
24.   , bukrs
    
25.   , waers
    
26.   , dmbtr*-1 as dmbtr
    
27.   , menge*-1 as menge
    
28.   , vlfkz
    
29.   , mtart
    
30.   , wempf
    
31.   , umwrk
    
32.   , xauto
    
33.   , kzzug
    
34.   , wgbez_1
    
35.   , zyear
    
36.   , kbetr
    
37.   , band
    
38.   , zdate
    
39.   , ukurs
    
40.   , shop_number
    
41.   from dwd.dwd_ret_exf_mdkcls
    
42.   where (vlfkz = 'B' and sobkz ='K'and bwart ='101'and shkzg= 'S'and kzzug='X'and ltrim (werks,'0') in ('DC20','DC21','DC22'))
    
43.   or (vlfkz = 'B' and sobkz ='K' and bwart ='207'and shkzg= 'S')
    
44.   or (vlfkz = 'B' and sobkz ='K' and bwart ='305'and shkzg= 'S'and ltrim (werks,'0') in ('DC20','DC21','DC22'))
    
45.   or (vlfkz = 'B' and sobkz ='K' and bwart ='208'and shkzg= 'H')
    
46.   or (vlfkz = 'B' and sobkz ='K'and lgort in ('1400','1100','1000')and bwart ='315'and shkzg= 'S')
    
47.   or (vlfkz = 'A' and sobkz ='K'and bwart ='305'and shkzg= 'S')
    
48.   or (vlfkz = 'A' and sobkz ='K'and bwart ='306'and shkzg= 'H')
    
49.   or (vlfkz = 'A' and sobkz ='K'and bwart ='101'and shkzg= 'S'and  ltrim (werks,'0') in ('AU07','DU01','DU02'))
    
50.   or (vlfkz = 'B' and sobkz ='K' and lgort in ('100','200') and bwart ='102'and shkzg= 'H'and kzzug='X'and ltrim (werks,'0') in ('DC20','DC21','DC22'))

复制代码

丝毫看不懂啊。

这通常是非SAP开发的ITer写出的代码，直接在数据库上建视图写完代码，在贴到SAP中，称为native sql，如果数据库时oracle，则为oracle sql语法，网上直接查看相应语法即可，其中ltrim(werks,'0')，是sql常用函数，表示去除地点中的0，这种写法是纯技术，不理解业务含义，维护时心累，强烈不推荐这种写法