Mysql计算天表的下雨天

Question

我想知道在一段时间内下雨（雨> 0.1）多少天咨询mysql。

我使用此代码，但它给我回所有的日子，有和无雨

$result = mysqli_query($con,"SELECT City, count(Rain > '0.1') as Total FROM Meteo2 where Data BETWEEN '" . split($_POST["date6"]) ."' AND '" . split($_POST["date7"]) ."' group by City"); 

TKS

Answer 1

功能count()计数non-NULL值的数量。我想你想要sum()：

select sum(Rain > 0.1) 
. . . 

的MySQL把布尔值作为整数，0假，1真正的。所以总和你想要的，而不是数。

Answer 2

$result = mysqli_query($con,"SELECT City, count(SELECT Rain FROM Meteo2 WHERE Rain > '0.1') as Total FROM Meteo2 where Data BETWEEN '" . split($_POST["date6"]) ."' AND '" . split($_POST["date7"]) ."' group by City"); 

Answer 3

总和城市

$result = mysqli_query($con,"SELECT City, SUM(SELECT Rain FROM Meteo2 WHERE Rain > '0.1') as Total FROM Meteo2 where Data BETWEEN '" . split($_POST["date6"]) ."' AND '" . split($_POST["date7"]) ."' GROUP BY City");