用户表user中存在一个名字字段username,现查询名字字段中包含"凤"的用户,下列SQL语句中,正确的是()
A: select * from user where username = '凤';
B: select * from user where username like '%凤%';
C: select * from user where username like '_凤_';
D: select * from user where username like '凤';
A: select * from user where username = '凤';
B: select * from user where username like '%凤%';
C: select * from user where username like '_凤_';
D: select * from user where username like '凤';
举一反三
- 从数据表中查询用户信息,以下语句中不正确的是( ) 。 A: select<br/>* from user; B: select<br/>username,password from user; C: select<br/>* from user order username; D: select<br/>* from user where username="admin";
- 以下语句哪个是正确的Select查询语句( ) A: select * from use B: select distinct username user; C: select * from user where ; D: select * from user username=’李四’;
- 以下可以正确运行的查询语句有( ) A: select * from user ; B: select * from user where username =’李四’; C: select * from user where 1=1; D: select distinct * from user;
- 已知用户表 user 有多列,其中字段 id 没有 NULL 值,字段username有NULL值,选项中,不能获得 user 表的总记录数量的 SQL 语句是 A: SELECT COUNT (*) FROM user ; B: SELECT COUNT ( id ) FROM user ; C: SELECT COUNT ( username ) FROM user ; D: SELECT COUNT ( id ) FROM user WHERE 1=1;
- 假定用户表user有多列，其中字段id中没有null值，字段username中存在null值。下面选项中，不能获得user表的总记录数的SQL语句是（ ） A: select count(*) from user; B: select count(id) from user; C: select count(username) from user; D: select count(id) from user where1=1;