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只是一個快速而簡單的問題,沒有太複雜的。
我正在MySQL中創建一個函數,它返回一個特定航班的總收入,我的問題是這樣的;我可以COUNT()where paymentType = 1的值,然後乘以機票價格乘以它們嗎?我確實嘗試過,但由於某種原因,它並沒有增加。的我在想什麼
例子:MySQL - 計數()和乘以400的結果
SELECT COUNT(paymentType * 400) FROM booking
WHERE paymentType = 1;
這裏是開始和結束$$之間的代碼。
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;
嘗試'SELECT COUNT(paymentType)* 400 FROM booking' –
我是一個白癡,你很有幫助,非常感謝! –