配置信息 public static final String USER_NAME = “root”; public static final String PWD = “123456789”; public static final String DRIVER = “com.mysql.jdbc.Driver”; public static final S…
上篇文章《实用sql查询语句详解1:给列取别名、查询部分行、多列排序》介绍了简单查询语句,这节课给大家讲解基本条件查询、集合函数、分组查询、子查询、并集和交集。 基本条件查询 比较运算符:>,>=,<,<=,=,!= between a and b,in(a,b,c),not exists,is null,like ‘%_’,or,a…