MySQL算术减法

Question

我有一张这样的表：

MYSQL 
table_01            tablo_02

Calculated tax      Deductible tax
--------------      ---------------
1200                2100
2305                5200
3250                1200    
2501                3215

我想要这样的结果

total table_01 - total table_02 = result

Answer 1

这样的事情：

select (
        select sum(calculated_tax)
        from table_01
        ) - (
        select sum(deductible_tax)
        from table_02
        ) as result