计算MySql中每个键类型的平均值

Question

我有一个表格保存这样的记录

a, 5
a, 6
a, 7
a, 8
b, 1
b, 2
b, 3
c, 1
c, 2
c, 3
c, 4
c, 5

我想要每个键的平均值 - ＆gt;

a, (5+6+7+8)/4 = 6.5
b, ..
c, ..

任何提示？

Answer 1

let column item and value, so your table like this

item,value
a, 5
a, 6
a, 7
a, 8
b, 1
b, 2
b, 3
c, 1
c, 2
c, 3
c, 4
c, 5

SELECT item,AVG(VALUE) as avg FROM Test.Testing GROUP BY item;

item ,avg
a, 7.2500
b, 2.0000
c, 2.5000