合并 SQL 中数据集的两个版本

Question

我有这样的数据：

email | ticket | date
a     |    1   | 1/1/2015
a     |    1   | 2/1/2015
a     |    3   | 5/6/2016
b     |    1   | 3/4/2016
b     |    2   | 7/9/2016
b     |    2   | 3/2/2016

我想通过两种不同的潜在布局对不同日期的门票求和：

email | ticket | date
a     |    2   | 2015
a     |    3   | 2016
b     |    5   | 2016

email | 2015 tickets | 2016 tickets
a     |    2         |     3
b     |    0         |     5

Answer 1

你只需要汇总。

--Query 1
select email,sum(ticket),extract(year from date) 
from tablename
group by 1,3

--Query 2
select email
,sum(case when extract(year from date) = 2015 then ticket else 0 end)
,sum(case when extract(year from date) = 2016 then ticket else 0 end)
from tablename
group by email