MySQL Round（）函數將不會舍入

Question

正在運行MySQL版本5.5.3。 我有這樣的代碼：

SELECT DISTINCT model, round(avg(overallRating),1) 
FROM car_ratings, car_details 
WHERE car_ratings.carId = car_details.carId 
AND make = 'HOLDEN' 
GROUP BY model 
ORDER BY avg(overallRating) DESC, model ASC 

這給了我'霍爾頓內使車輛的平均評價每個模型的。它工作正常，除了將數字從4.050增加到4.1。有沒有辦法讓這個數字下降？所以它給了我4.0而不是4.1。

Answer 1

您是否希望在所有情況下進行調整？如果是這樣，你正在尋找FLOOR

http://dev.mysql.com/doc/refman/5.0/en/mathematical-functions.html#function_floor

SELECT DISTINCT model, FLOOR(avg(overallRating) * 10)/10 -- HERE 
FROM car_ratings, car_details 
WHERE car_ratings.carId = car_details.carId 
AND make = 'HOLDEN' 
GROUP BY model 
ORDER BY avg(overallRating) DESC, model ASC