#MySQL 5.7.12

#please drop objects you've created at the end of the script 

#or check for their existance before creating

#'\\' is a delimiter

​

drop table table1;

drop table table2;

​

create table Table1(

id  int,  

main    int,

rate int

);

​

insert into table1 values(1,10,3);                     

​

create table table2(

id    int,

table1_id  int,   

value    int,

newnum int

);

​

insert into table2 values(1,1,20,3);

insert into table2 values(2,1,30,2);

insert into table2 values(3,1,22,3);

insert into table2 values(4,1,0 ,0);

​

​

SELECT table1_result,

       table2_result,

       table1_result + table2_result AS FINAL

FROM

  (SELECT id,

          sum(main*rate) AS table1_result

   FROM table1 t1