题目: create table my_001 (id int,value int); insert into my_001 values(1,10): insert into my_001 values(2,20): insert into my_001 values(3,15): 结果 id value sum 1 10 10 2 20 30 3 15 45 sql:select t1.id,t1.value ,sum(t2.value) from my_001 t1,join my_001…