選擇每個組的最大值

Name Value AnotherColumn 
----------- 
Pump 1 8000.0 Something1 
Pump 1 10000.0 Something2 
Pump 1 10000.0 Something3 
Pump 2 3043 Something4 
Pump 2 4594 Something5 
Pump 2 6165 Something6

我的表看起來像這樣。我想知道如何選擇每個泵的最大值。選擇每個組的最大值

select a.name, value from out_pumptable as a, 
(select name, max(value) as value from out_pumptable where group by posnumber)g where and g.value = value

這個代碼的工作，但我得到泵1的兩個條目，因爲它有兩個條目具有相同的值。

來源

2010-12-22 Wai Wong

SELECT 
    b.name, 
    MAX(b.value) as MaxValue, 
    MAX(b.Anothercolumn) as AnotherColumn 
FROM out_pumptabl 
INNER JOIN (SELECT 
       name, 
       MAX(value) as MaxValue 
      FROM out_pumptabl 
      GROUP BY Name) a ON 
    a.name = b.name AND a.maxValue = b.value 
GROUP BY b.Name

請注意，如果您有主鍵，這將更容易。下面是一個例子

來源

2010-12-22 14:31:57

啊，當。我讓這個例子太簡單了。有更多的列表，這使它有點複雜>。< – 2010-12-22 14:33:37

如果更多的列只是將它們添加到選擇 – 2010-12-22 14:34:31

130

select name, max(value) 
from out_pumptable 
group by name

來源

2010-12-22 14:32:28

-2

SELECT DISTINCT (t1.ProdId), t1.Quantity FROM Dummy t1 INNER JOIN 
     (SELECT ProdId, MAX(Quantity) as MaxQuantity FROM Dummy GROUP BY ProdId) t2 
    ON t1.ProdId = t2.ProdId 
    AND t1.Quantity = t2.MaxQuantity 
ORDER BY t1.ProdId

這會給你的想法。

來源

2011-10-08 11:28:45

select name, value 
from(select name, value, ROW_NUMBER() OVER(PARTITION BY name ORDER BY value desc) as rn 
from out_pumptable) as a 
where rn = 1

來源

2018-01-26 09:03:54 twk7890

選擇每個組的最大值

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