sql - Case 语句中的条件

Question

select min(measurement), part_desc
    (case len(measurement)
        when 6 then '0000' + part_desc
        else '000' + part_desc
        end)
from LeachingView
where DateTimeStamp > '2011-01-01' and measurement > 0
group by measurement, part_desc

应该将 0000 附加到另一个字符的前面，但它不起作用，我想知道为什么以及如何使它正确。

我得到的错误是这样的：

“part_desc”不是可识别的内置函数名称。

Answer 1

根本不需要CASE...

select
    min(measurement),
    RIGHT('0000000000' + part_desc, 10) AS part_desc
from...

Answer 2

select min(measurement), 
    case len(measurement)
        when 6 then '0000' + part_desc
        else '000' + part_desc
    end as part_desc
from LeachingView
where DateTimeStamp > '2011-01-01' 
    and measurement > 0                        
group by case len(measurement)
        when 6 then '0000' + part_desc
        else '000' + part_desc
    end

Answer 3

我想你想要

Select min(measurment),
       (case len(measurement)
         when 6 then '0000' + part_desc
         else '000' + part_desc
        end) AS "part_desc"
From LeachingView
Where...