I have: create table tbl (a,b,c,d,e,f,g,h); And i need to select in 1 query ,or the most performant way:
top 5(a) top 5(b) top 5(c): for each top5(c): top 5(d) count(f) GROUP BY f I can make these in separate queries but that means that postgresql would read the table multiple-times? Is it possible/doable/sane ? Thanks
