Question

我有状态表并存储56个状态和ID，我根据存储在[Cases]表中的ID更新FieldValue表中的值列。我可以用case语句来得到结果，我不想重复56次案例陈述

Update cv 
set Value = 
        case when 
            c.[state] = 1 then 13
            c.[state] = 2 then 14
            c.[state] = 3 then 15
            .
            .
            .
        End     
from 
    [Cases]  c
join 
    [files] f on f.FileName  = c.Name 
join 
    Recordset CR on CR.RecordId = f.id and RecordId = 3
join 
    FieldValue cv on cv.RecordsetId = cr.Id and cv.FieldId = 6
where 
    c.[State] is not null

Answer 1

如果state和要更新的值有某种关系（比如我在你的例子中看到的值= state + 12）你可以做

update cv
set value = c.[state] +12
from [Cases]  c
join [files] f on f.FileName  = c.Name 
join Recordset CR on CR.RecordId = f.id and RecordId = 3
join FieldValue cv on cv.RecordsetId = cr.Id and cv.FieldId = 6
where c.[State] is not null

如果根本没有关系，你需要写56行或者一个返回预期值的函数（里面它将是56行），这是一个更好的aproch，以防需要新的值未来

update cv
set value = fn_value_from_state(c.[state])
from [Cases]  c
join [files] f on f.FileName  = c.Name 
join Recordset CR on CR.RecordId = f.id and RecordId = 3
join FieldValue cv on cv.RecordsetId = cr.Id and cv.FieldId = 6
where c.[State] is not null

即使在第一种情况下，如果值 - 状态关系发生变化，函数也会更好

简短的更新表

1 个答案: