求一句sql语句

Question

select prfnum,sum(decode(statuspro,2,1,0)) "statuspro=2",sum(decode(statuspro,1,1,0)) "stautspro=1" from tb group by prfnum;

Answer 1

select prfnum ,
       sum(decode(statuspro,2,1,0)) as statuspro2 ,
       sum(decode(statuspro,1,1,0)) as statuspro1
from
       表
group by prfnum 
order by prfnum

Answer 2

prfnum   statuspro
1          2
1          2
1          2
2          1
2          2
3          1
3          1结果
prfnum  statuspro=2 stautspro=1
1             3         0
2             1         1
3             0         2
select prfnum,sum(case when statuspro=2 then 1 else 0 end) "statuspro=2",sum(case when statuspro=1 then 1 else 0 end) "statuspro=1" from your_tablename group by prfnum

Answer 3

select prfnum,sum(decode(statuspro,2,1,0)) "statuspro=2",sum(decode(statuspro,1,1,0)) "stautspro=1" from tb group by prfnum;

Answer 4

建议写这种SQL时，尽量使用decode，decode在oracel中，会经常使用！功能很强大，可以深入研究