多个列上的SQL唯一计数

Question

I am new to SQL so don't know much about it. Please help. I have a database something like this:

User    Model
A        X
A        X
A        X
B        Y
C        Y
C        Y
D        X
D        X
E        Z....

I want to calculate the frequency of the each unique model respective to unique users. I mean the output should be something like this:

Model    Count
 X         2
 Y         2
 Z         1

as A and D use model X, so X=2. Similarly B and C use model Y, so Y=2. and same goes for Z(only user E). How do I achieve this?

Answer 1

Use group by .

select model,count(distinct user)
from tbl
group by model