php - Mysql在单个php页面上进行多个查询以求和各个表

Question

假设我想在 3 个不同的表上执行 3 个不同的总和

SELECT sum(`diepoints`)  as exp FROM `dies` where user='coder'
SELECT sum(`winpoints`)  as rev FROM `wins` where user='coder'
SELECT sum(`debtpoints`) as deb FROM `debts` where user='coder'

我想在一条语句中执行这些查询。

$resource1= $con->query(SELECT sum(`diepoints`)  as exp FROM `dies` where user='coder');
$resource2 = $con->query(SELECT sum(`winpoints`)  as rev FROM `wins` where user='coder');
$resource3 = $con->query(SELECT sum(`debtpoints`) as deb FROM `debts` where user='coder');

然后将它们按如下所示放置。

Echo "Your total die points are".$row['exp'];
Echo "Your total die points are".$row['rev'];
Echo "Your total die points are".$row['deb'];

任何关于如何组合这些查询的帮助解释都会很棒。

Answer 1

一种简单的方法是子查询:

SELECT (SELECT sum(`diepoints`)  as exp FROM `dies` where user='coder') as exp,
       (SELECT sum(`winpoints`)  as rev FROM `wins` where user='coder') as rev,
       (SELECT sum(`debtpoints`) as deb FROM `debts` where user='coder') as deb