〇、概述
1、内容介绍
条件查询:比较、不等于、IN、为空、BETWEEN
2、建表语句
drop table if exists user_profile;
CREATE TABLE `user_profile` (
`id` int NOT NULL,
`device_id` int NOT NULL,
`gender` var...
我照着书上的例子写下了如下代码,运行后发现提示Nil cannot be assigned to type 'Int'
var i:Int?=
if i!=nil {//Nil cannot be assigned to type 'Int'
print("not nil")
}
else{
print("nil")
}
检查...
python not equal operator returns true if two variables are of same type and have different values, if the values are same then it returns false.
如果两个变量具有相同的类型并且具有不同的值 ,则py...