是否可以简化以下案例陈述,或者我是否已经拥有它最优雅的形式?
select case when Ks2en = '' then 'No KS2' else ks2en end as 'KS2',
nullif(count(case result when '' then 1 end),0) as 'No Result',
nullif(count(case result when 'U' then 1 when '1a' then 1 when '1b' then 1 when '1c' then 1 end),0) as '1/U',
nullif(count(case result when 'U' then 1 when '2a' then 1 when '2b' then 1 when '2c' then 1 end),0) as '2/U',
nullif(count(case result when 'G-' then 1 when '3c' then 1 end),0) as '3c/G-',
nullif(count(case result when 'G' then 1 when '3b' then 1 end),0) as '3b/G',
nullif(count(case result when 'G+' then 1 when '3a' then 1 end),0) as '3a/G+',
nullif(count(case result when 'F-' then 1 when '4c' then 1 end),0) as '4c/F-',
nullif(count(case result when 'F' then 1 when '4b' then 1 end),0) as '4b/F'
**snip**
from student join subject
on subject.upn=student.upn
where name='English'
group by ks2en
order by
case when ks2en = 'W' Then 0 Else 1 End,
left(ks2en, 1),
right(ks2en, 1) desc
它生成以下网格,我希望这个结果保持不变:
KS2 No Result 1/U 2/U 3c/G- 3b/G 3a/G+ 4c/F- 4b/F **snip**
No KS2 1 NULL NULL NULL NULL NULL NULL **snip**
2a NULL NULL NULL NULL NULL NULL 2 1 **snip**
3c 1 NULL NULL NULL NULL NULL NULL NULL **snip**
3b NULL NULL NULL NULL NULL NULL 1 NULL **snip**
3a 1 NULL NULL NULL NULL NULL NULL NULL **snip**
4c NULL 1 1 NULL NULL NULL NULL NULL **snip**
4b NULL NULL NULL NULL NULL NULL NULL NULL **snip**
4a NULL 1 1 NULL NULL NULL NULL NULL **snip**
5c NULL NULL NULL NULL NULL NULL NULL NULL **snip**
5b NULL NULL NULL NULL NULL NULL NULL NULL **snip**
为了简洁起见,我已经剪掉了代码和结果,但是 sql 包含更多的案例,以便创建总计列。