Question

我使用了以下查询

select month(SubmittedDate), count(policyid) from tblpolicy p join tlkppolicystatus s on p.StatusID=s.StatusID where SubmittedDate between 
'2017-01-01' and sysdate()  and s.StatusID=1 group by month(SubmittedDate);

这将返回以下输出，该输出正确为月号3和4没有任何数据。

Month  Total
-----|-----
1    | 62
2    | 34
5    | 1

但我希望输出像

Month  Total
-----|-----
1    | 62
2    | 34
3    | 0
4    | 0
5    | 1

这意味着如果任何月份有任何数据，那么它也将显示值0

由于

Answer 1

试试这个

select coalesce(t1.month,t2.month) as month, coalesce(ct1.count,0) as count from 
(
select month(SubmittedDate) as month, count(policyid) as count 
 from tblpolicy p join tlkppolicystatus s on p.StatusID=s.StatusID 
 where SubmittedDate between 
'2017-01-01' and sysdate()  and s.StatusID=1 group by month(SubmittedDate)
) as t1 right join 
(
select 1 as month union all
select 2 as month union all
select 3 as month union all
select 4 as month union all
select 5 as month union all
select 6 as month union all
select 7 as month union all
select 8 as month union all
select 9 as month union all
select 10 as month union all
select 11 as month union all
select 12 as month 
) as t2 on t1.month <= t2.month;

Answer 2

如果您有所有月份的数据，但没有数据的状态为1，那么最简单的方法可能是使用条件聚合：

select month(SubmittedDate), sum(s.StatusID = 1)
from tblpolicy p join
     tlkppolicystatus s
     on p.StatusID=s.StatusID
where SubmittedDate between '2017-01-01' and sysdate()
group by month(SubmittedDate);

当然，如果这些条件不成立，那么带有派生表的left join是最佳解决方案。

结果组中的不可用行

2 个答案: