Select max value of each group
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
My table looks something like this. I would like to know how to select max value for each pump.
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
this code does the job, but i get two entries of Pump 1 since it has two entries with same value.
Solution 1:
select name, max(value)
from out_pumptable
group by name
Solution 2:
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
Note this would be far easier if you had a primary key. Here is an Example
SELECT * FROM out_pumptabl c
WHERE PK in
(SELECT
MAX(PK) as MaxPK
FROM out_pumptabl b
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)
Solution 3:
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