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我有一個表列日期,系統,硬度,電導率,tankno。mysql多表連接表
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
我想這樣
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
報告我使用這個SQL語句:
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'
但有關地方tankno 1個值可用這樣的日期,這個返回數據:
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,以便獲取數據所有日期
我想從日期列的所有日期,並將其加入到所有坦克1個vlaues和罐2個值
非常感謝。自昨天上午以來,我一直在燒我的手指 – mansoondreamz