How to implement partition by function in LookML

[lumiaowpi]

There is a table, for example
Product / Order / Price
A / 1 / $6
A / 2 / $11
A / 3 / $7
B / 4 / $8
B / 5 / $12
B / 6 / $2

I want to return the first order for each product
Product / Order / Price
A / 1 / $6
B / 4 / $8