SAS proc means equivalent in Redshift

Question

I want to convert a SAS code into redshift code. We have proc means procedure in SaS,

proc means data=table0 noprint, nway missing;
id a ,b
class  x
var qty
output out=table1 sum = ;

Example: Input

Required Output:

I wanted an equivalent code in redshift. The usual group by will not work here.