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参考表:student

MySQL笔记之基本查询的应用详解

多字段查询
复制代码 代码如下:
mysql> select id,name,birth from student;


所有字段查询
复制代码 代码如下:
mysql> select * from student;


where指定查询
复制代码 代码如下:
mysql> select * from student where id=901;
mysql> select * from student where id>=904;
mysql> select name from student where department='计算机系';


in指定集合查询
复制代码 代码如下:
mysql> select * from student where birth in(1988,1990);
mysql> select * from student where id in(903,906);

not in非范围查询
复制代码 代码如下:
mysql> select * from student where birth not in(1990,1998);


between and指定范围查询
复制代码 代码如下:
mysql> select * from student where birth between 1986 and 1988;


not between and不在指定范围的查询
复制代码 代码如下:
mysql> select * from student where id not between 904 and 906;


like字符串匹配查询
复制代码 代码如下:
mysql> select * from student where name like '_三';
mysql> select * from student where name like '张三';
mysql> select * from student where name like '张%';


not like不匹配查询
复制代码 代码如下:
mysql> select * from student where name not like '张%';


null查询
复制代码 代码如下:
mysql> select * from student where address is null;


and多条件查询
复制代码 代码如下:
mysql> select * from student where name like '张%' and birth>1985;
mysql> select * from student where name like '张%' and birth>1985 and id like '%3';


or多条件查询
复制代码 代码如下:
mysql> select * from student where id=905 or birth=1988;
mysql> select * from student where id=905 or birth=1988 or sex='女';

distinct查询结果不重复
复制代码 代码如下:
mysql> select distinct sex from student;
mysql> select distinct department from student;


order by查询结果排序
复制代码 代码如下:
mysql> select * from student order by birth;
mysql> select * from student order by birth asc;
mysql> select * from student order by birth desc;


group by分组查询
复制代码 代码如下:
mysql> select sex,group_concat(name) from student group by sex;
mysql> select sex,count(name) from student group by sex;


正则表达式查询
复制代码 代码如下:
mysql> select * from student where birth regexp '1988|1990';


limit限制查询结果数量
复制代码 代码如下:
mysql> select * from student limit 2;
mysql> select * from student limit 1,3;


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P70系列延期,华为新旗舰将在下月发布

3月20日消息,近期博主@数码闲聊站 透露,原定三月份发布的华为新旗舰P70系列延期发布,预计4月份上市。

而博主@定焦数码 爆料,华为的P70系列在定位上已经超过了Mate60,成为了重要的旗舰系列之一。它肩负着重返影像领域顶尖的使命。那么这次P70会带来哪些令人惊艳的创新呢?

根据目前爆料的消息来看,华为P70系列将推出三个版本,其中P70和P70 Pro采用了三角形的摄像头模组设计,而P70 Art则采用了与上一代P60 Art相似的不规则形状设计。这样的外观是否好看见仁见智,但辨识度绝对拉满。