winfwu

摘要： 『1』对查询结果进行排序（默认是按照Asc排序方式排序） select * from employee order by age; 『2』对查询结果进行Eesc排序 select * from employee order by age desc; 『3』多次排序 select * from employee order by d_id asc,age asc; 『4』order by和group_concat函数连用 select sex,group_concat(name) from employee group by sex; 『5』GROUP BY 关键字与COUNT(... 阅读全文

摘要： 『1』IS NULL查询空值 select * from work; select * from work where sex is null; 『2』多AND条件查询； 表结构如上work； select * from work where name='w3' and id=3 and sex='男' and info='info1'; 『3』多OR条件查询 表结构如上work; select * from work where name='w3' or id=2 or sex='女'; 『4』DISTINCT关 阅读全文

摘要： 『1』带IN关键字查询 用select * from employee;查询到表结构如下 使用select * from employee where d_id in(1001,1004);SQL语句查询结果如下 使用select * from employee where d_id not in(1001.1004);SQL语句查询结果如下 『2』BETWEEN AND关键字查询 使用employee表做为数据库表。 用select * from employee where d_id between 1003 and 1004; 用select * from e... 阅读全文