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题解 | #查找后排序#

select device_id,age from user_profile order by age asc; // order by + 列名 asc/desc:根据那一列升序/降序

Mysql

2022-03-13

9 810

题解 | #操作符混合运用#

select device_id,gender,age,university,gpa from user_profile where gpa > 3.5 AND university = '山东大学' union ...

Mysql

2022-03-11

12 1670

题解 | #操作符混合运用#

select device_id,gender,age,university,gpa from user_profile where (gpa > 3.5 AND university = '山东大学') or ...

Mysql

2022-03-11

0 197

题解 | #Where in 和Not in#

select device_id,gender,age,university,gpa from user_profile where university in ('北京大学','复旦大学','山东大学'); //in/not in + (集合中存放列值)

Mysql

2022-03-11

0 220

题解 | #高级操作符练习(2）#

select device_id,gender,age,university,gpa from user_profile where university = '北京大学' or gpa > 3.7; //or: //一真则真，全假则假

Mysql

2022-03-11

0 243

题解 | #高级操作符练习(1)#

select device_id,gender,age,university,gpa from user_profile where gender = 'male' and gpa > 3.5; //and //全真则真...

Mysql

2022-03-11

0 328

题解 | #用where过滤空值练习#

select device_id,gender,age,university FROM user_profile WHERE age != '';//1.不为空1 WHERE age is not null;//2.不为空2

Mysql

2022-03-11

0 227

题解 | #查找除复旦大学的用户信息#

select device_id,gender,age,university FROM user_profile WHERE university not like '复旦大学';//1.模糊查询列值中不含有复旦大学四个字儿 WHERE university...

Mysql

2022-03-11

46 404

题解 | #查找某个年龄段的用户信息#

SELECT device_id,gender,age FROM user_profile WHERE age BETWEEN 20 and 23; //注意：BETWEEN 20 and 23 是闭区间[20,23]。

Mysql

2022-03-11

0 274

题解 | #查询结果限制返回行数#

select device_id AS user_infos_example from user_profile LIMIT 2; //1.as 写不写都可 //2.别名加不加引号（单双）都可 //加引号：别名就是引号内的内容。 //不加引号：别名如果为小写，会解析为大写，别名实际为大写。 //...

Mysql

2022-03-10

71 1188