Mysql 查询加减法

Question

select
    sum(Account_recharge) as 'Total Recharge',
    sum(Amount_Received) as 'Total Received'
from insert1
cross join received1
    on insert1.id = received1.id
where insert1.Account_Name = 'arvind2';

total recharge    Total received
 1000              500

但我还想显示会费=500

Answer 1

取充值总额与收到总额的差额？

SELECT
    SUM(Account_recharge) AS `Total Recharge`,
    SUM(Amount_Received) AS `Total Received`,
    SUM(Account_recharge) - SUM(Amount_Received) AS dues
FROM insert1 i1
INNER JOIN received1 r1
    ON i1.id = r1.id
WHERE
    i1.Account_Name = 'arvind2';

请注意，我用内部联接替换了交叉联接。交叉连接在这里没有意义，因为连接有一个标准(尽管显然它在 MySQL 中为您工作)。