Question

附录一

ID  Marks1  Marks2  Marks3
-------------------------
1   10      0       4
2   0      40       90

现在,我需要首先从这个桌子上选择积极的价值观。因此,如果标记为0,则该标记将转而正确。选任考试委员会应在产出之后提供

ID  Marks1  Marks2  Marks3
-------------------------
1   10      4       0
2   40      90      0

您能否指导我采取这种做法? 如果能够在某种发言中进行,那将是巨大的。提前感谢。

Answer 1

如同你一样,你需要检查下几行,即上列第0栏。

Select
Coalesce(Marks1, Marks2, Marks3,0) as Marks1,
Case when marks1 is not null 
     then Coalesce(Marks2, Marks3, 0) else 0 
end as Marks2,
case when marks1 is not null 
     and marks2 is not null 
     then Coalesce(Marks3,0) 
end as Marks3

from
(
Select
Case when Marks1 =0 then null else Marks1 end as Marks1,
Case when Marks2 =0 then null else Marks2 end as Marks2,
Case when Marks3 =0 then null else Marks3 end as Marks3
  From mytbl
)

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