检查此SQL查询

Question

select a.LOB, SUM(a.GPW) AS XGPW,SUM(b.GPW) AS YGPW,SUM(a.GPW) - SUM(b.GPW)     AS GPW_DIFF 
FROM SDSS.DSS_SALES_PRODUCTION_DTLS a,

SDSS.DSS_SALES_PRODUCTION_DTLS b 
where a.LOB = b.LOB and
a.account_year=2014 and b.account_year=2015
GROUP BY a.LOB

我想打印2014年和2015年产生的总GPW。在Db中，我每个月都有单独的GPW值等，我想将它们全部加起来。对于2014年，总和是正确的但不是2015年。建议

Answer 1

不要两次加入同一个表，而是最好使用CASEes：

SELECT LOB, XGPW, YGPW, XGPW - YGPW AS GPW_DIFF 
from 
 (
   select LOB, 
      SUM(CASE WHEN account_year=2014 THEN a.GPW ELSE 0 END) AS XGPW,
      SUM(CASE WHEN account_year=2015 THEN a.GPW ELSE 0 END) AS YGPW,
   FROM SDSS.DSS_SALES_PRODUCTION_DTLS
   where account_year in (2014, 2015)
   GROUP BY LOB
 ) dt

Answer 2

您需要像这样更改and条件：

a.account_year in(2014,2015)

<击> 所以它就像

select a.LOB, SUM(a.GPW) AS XGPW,SUM(b.GPW) AS YGPW,SUM(a.GPW) - SUM(b.GPW)     AS GPW_DIFF 
FROM SDSS.DSS_SALES_PRODUCTION_DTLS a,

SDSS.DSS_SALES_PRODUCTION_DTLS b 
where a.LOB = b.LOB and
a.account_year in(2014,2015)
GROUP BY a.LOB

<击> 修改

SELECT LOB, XGPW, YGPW, (XGPW - YGPW) AS GPW_DIFF 
from 
 (
   select LOB, 
    SUM(CASE WHEN account_year=2014 THEN GPW ELSE 0 END) AS XGPW,
    SUM(CASE WHEN account_year=2015 THEN GPW ELSE 0 END) AS YGPW,
   FROM SDSS.DSS_SALES_PRODUCTION_DTLS
   where account_year in (2014, 2015)
   GROUP BY LOB
 ) x

Answer 3

＆＃34; OR＆＃34;需要而不是＆＃34; AND＆＃34;。

select a.LOB, SUM(a.GPW) AS XGPW,SUM(b.GPW) AS YGPW,SUM(a.GPW) - SUM(b.GPW)     AS GPW_DIFF 
FROM SDSS.DSS_SALES_PRODUCTION_DTLS a,

SDSS.DSS_SALES_PRODUCTION_DTLS b 
where a.LOB = b.LOB and
(a.account_year=2014 or b.account_year=2015)
GROUP BY a.LOB