我正在写一份报告,显示自去年以来每个月的代码总量。
目前,如果我只计算过去一年中的所有代码,那么我的结果集将如下所示
name | code | total | date
build1 x1 10 04-2013
build1 x50 60 05-2013
build1 x1 80 06-2013
build1 x90 450 07-2013
我能够转置所有的行,所以所有的列都是月份,下面是总数。我的更新结果现在看起来像这样
name | code | apl | may | jun | jul
build1 x1 10 0 80 0
build1 x50 0 60 0 0
build1 x90 0 0 0 450
上面的代码是我正在寻找的结果,但我现在想要做的是在当月之前订购所有东西,然后从当月起倒退一年。
因此,如果当前月份是 7 月,那么我的结果集将像这样排序
name | code | jul | jun | may | apl
build1 x1 0 80 0 10
build1 x50 0 0 60 0
build1 x90 450 0 0 0
我遇到的问题是我使用别名作为月份名称。而且您无法从别名中获取月份。此外,据我所知,别名是静态的,因此一旦设置它们就无法更改。将月份作为列名的唯一方法是从数据集中提取它。但是当我将行转换为列时,我必须使用别名,因为我使用案例语句来获取每个月的所有总数。
编辑:对不起,postgresql 版本是 8.4,这是我到目前为止的查询
SELECT
pname,
code,
SUM(totaljanurary) AS "Janurary",
SUM(totalfebruary) AS "February",
SUM(totalmarch) AS "March",
SUM(totalapril) AS "April",
SUM(totalmay) AS "May",
SUM(totaljune) AS "June",
SUM(totaljuly) AS "July",
SUM(totalaugust) AS "August",
SUM(totalseptember) AS "September",
SUM(totaloctober) AS "October",
SUM(totalnovember) AS "November",
SUM(totaldecember) AS "December"
FROM(
SELECT
pname,
code,
SUM(case when extract (month FROM checked_date)=01 then total else 0 end) AS totaljanurary,
SUM(case when extract (month FROM checked_date)=02 then total else 0 end) AS totalfebruary,
SUM(case when extract (month FROM checked_date)=03 then total else 0 end) AS totalmarch,
SUM(case when extract (month FROM checked_date)=04 then total else 0 end) AS totalapril,
SUM(case when extract (month FROM checked_date)=05 then total else 0 end) AS totalmay,
SUM(case when extract (month FROM checked_date)=06 then total else 0 end) AS totaljune,
SUM(case when extract (month FROM checked_date)=07 then total else 0 end) AS totaljuly,
SUM(case when extract (month FROM checked_date)=08 then total else 0 end) AS totalaugust,
SUM(case when extract (month FROM checked_date)=09 then total else 0 end) AS totalseptember,
SUM(case when extract (month FROM checked_date)=10 then total else 0 end) AS totaloctober,
SUM(case when extract (month FROM checked_date)=11 then total else 0 end) AS totalnovember,
SUM(case when extract (month FROM checked_date)=12 then total else 0 end) AS totaldecember
FROM (
--START HERE
SELECT
pname,
code,
COUNT(code)AS total,
date_trunc('month',checked_date)::date AS checked_date
FROM table1
AND checked_date >= current_date-365
AND checked_date <= current_date
GROUP BY pname, code, date_trunc('month',checked_date)
)T1
GROUP BY pname, code, date_trunc('month',checked_date)
)T2
GROUP BY pname, code
ORDER BY pname, code