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只是一个快速而简单的问题,没有太复杂的。
我正在MySQL中创建一个函数,它返回一个特定航班的总收入,我的问题是这样的;我可以COUNT()where paymentType = 1的值,然后乘以机票价格乘以它们吗?我确实尝试过,但由于某种原因,它并没有增加。的我在想什么
例子:MySQL - 计数()和乘以400的结果
SELECT COUNT(paymentType * 400) FROM booking
WHERE paymentType = 1;
这里是开始和结束$$之间的代码。
DECLARE revenue INT;
SELECT COUNT(paymentType) INTO revenue FROM booking
INNER JOIN flights
ON booking.flightCode = flights.flightCode
WHERE paymentType = 1
AND flights.flightDate = flight_date
AND flights.flightNumber = flight_number;
RETURN revenue;
尝试'SELECT COUNT(paymentType)* 400 FROM booking' –
我是一个白痴,你很有帮助,非常感谢! –