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我有一个列日期,系统,硬度,电导率,tankno表。Sql获取行中的列值
date system cond hard tankno 2014-01-04 HT 55.67 2.68 1 2014-01-05 HT 64.67 3.1 2 2014-01-10 HT 54.77 2.44 1 2014-01-10 HT 66.3 3.47 2 2014-01-18 HT 55.63 2.38 1 2014-01-18 HT 65.9 1.44 2 2014-01-24 HT 53.1 1.76 2 2014-01-28 HT 64.53 2.1 1
我想这样
Date system Tank 1 cond Tank1 Hard Tank 2 cond Tank 2hard 2014-01-04 HT 55.67 2.68 NULL NULL 2014-01-05 HT NULL NULL 64.67 3.1 2014-01-10 HT 54.77 2.44 66.3 3.47 2014-01-18 HT 55.63 2.38 65.9 1.44 2014-01-24 HT NULL NULL 53.1 1.76 2014-01-28 HT 64.53 2.1 NULL NULL
报告我使用这个SQL语句:
select t1.date, t1.cond as tk1cond, t1.hard as tk1hard,
t2.cond as tk2cond, t2.hard as tk2hard
from systemvalue t1 left join systemavalue t2
on t1.date=t2.date
and t2.tankno='2'
and t2.system='HT'
and month(t2.date)='01'
and year(t2.date)='2014'
where t1.tankno='1' and t1.system='HT'
and month(t1.date)='01'
and year(t1.date)='2014'
但有关地方tankno 1个值可用这样的日期,这个返回数据:
Date system Tank 1 cond Tank1 Hard Tank 2 cond Tank 2hard 2014-01-04 HT 55.67 2.68 NULL NULL 2014-01-10 HT 54.77 2.44 66.3 3.47 2014-01-18 HT 55.63 2.38 65.9 1.44 2014-01-28 HT 64.53 2.1 NULL NULL
如何修改SQL,以便获取数据所有日期
我想从日期列的所有日期,并将其加入到所有坦克1个vlaues和罐2个值
OUTER JOIN不工作得值 – mansoondreamz