在刷代码的小师弟

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题解 | #用where过滤空值练习#

select device_id,gender,age,university from user_profile where age <> 'null'; # age is not null; # age != 'null';

2023-10-18

1 300

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'; # university != '复旦大学'; # university not in('复旦...

2023-10-18

1 205

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;

2023-10-18

1 191

题解 | #查找年龄大于24岁的用户信息#

select device_id,gender,age,university from user_profile where age > 24;

2023-10-18

1 204

题解 | #查找学校是北大的学生信息#

select device_id,university from user_profile where university = '北京大学';

2023-10-18

1 256

题解 | #将查询后的列重新命名#

select device_id as 'user_infos_example' from user_profile where id in(1,2);

2023-10-18

1 145

题解 | #查询结果限制返回行数#

select device_id from user_profile where id in(1,2);

2023-10-18

1 199

题解 | #查询结果去重#

select distinct university from user_profile; # distinct 去除重复

2023-10-18

1 144

题解 | #查询多列#

select device_id,gender,age,university from user_profile;

2023-10-18

1 161

题解 | #查询所有列#

select * from user_profile;

2023-10-18

1 238