История изменений
Исправление Rastafarra, (текущая версия) :
select table1.name, sum(tbl3.number) from table1
join tbl2 on table1.id2 = table2.id2
join tbl3 on tbl2.id3 = table3.id3
group by table1.name
Исходная версия Rastafarra, :
select table1,name, sum(tbl3.number) from table1
join tbl2 on table1.id2 = table2.id2
join tbl3 on tbl2.id3 = table3.id3
group by table1.name