salvatore

要获得转换率,可以使用 COUNT(*) 聚合函数 GROUP BY 条款。 类似于:

SELECT (COUNT(*)/(SELECT COUNT(*) FROM Order))*100 AS perc,ad_channel
FROM Order
LEFT JOIN Advertising ON Order.user_id = Advertising.user_id
GROUP BY ad_channel;

如果这是一个sql脚本,我建议您使用一个变量将其分为两个查询:

select @var := PRICE from PRODUCTS where ID = 1;
UPDATE PRODUCTS SET PRICE = @var;

在我看来,变量比临时表容易得多。

我还没有完全测试过,但是语法应该是