例如:
SELECT if(order_status>=1,sum(amount),0) as pay_amount,count(if(order_status>=1,true,null)) as...pay_num,if(order_status=2,sum(amount),0) as cancel_amount,count(if(order_status=2,true,null)) as cancel_num...-%d') as dateTime FROM `cdz_jiayou_order` WHERE `create_time` BETWEEN '2021-06-01' AND '2021-06-30' GROUP...然而, sum函数返回一个值类型的数值,sum此时if中第三个参数为0则无数据时返回0,为null无数据时则会返回null。...和count有着不一样的点就在这里。