table same id multiple name how to read

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SQL-Server

I have table customer

one custid has more than one prdId like,

cusid   prdId
1        1
1        2
2        1
3        1
4        1
4        2
4        3

How do i read a same cusid with different prdId

I want answer is is

1 [1,2]
2 [1]
3 [1]
2 [1,2,3]