MYSQL如何将两个连接字段相加

Question

Hi Do you have idea how to sum two defined fields? is this posible?

SELECT SUM(a) as total_a, SUM(b) as total_b, (total_a + total_b) as grand_total
FROM table

if not, how can i come-up with this?

Answer 1

You can also do it inline as in:

SELECT SUM(a) as total_a, SUM(b) as total_b, (sum(a) + sum(b)) as grand_total
FROM table

Answer 2

You need create a subquery.

SELECT sum_ab.total_a + sum_ab.total_b as grand_total
FROM 
  (SELECT SUM(a) as total_a, SUM(b) as total_b
   FROM table
  ) as sum_ab