• 2022-06-03
    下面选项中,能够更新user表中数据的SQL语句是()
    A: update into user set id = 'u001';
    B: update user set id = 'u001' and username='jack';
    C: update user set username='jack' where id = 1;
    D: update into user set id = 'u001', username='jack';
  • C

    内容

    • 0

      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;

    • 1

      下面通过UPDATE语句将root用户的密码修改为mypwd2的语句中,正确的是 A: UPDATE mysql.user SET Password=PASSWORD('mypwd2') WHERE User='root' and Host='localhost'; B: UPDATE mysql.users SET Password=PASSWORD('mypwd2') WHERE User='root' and Host='localhost'; C: UPDATE mysql.users SET Password=PASSWORD('mypwd2') WHERE User='root' OR Host='localhost'; D: UPDATE mysql.user SET Password=PASSWORD('mypwd2') WHILE User='root' OR Host='localhost';

    • 2

      更新student表id=1的记录,name值更新为”youjun”,grade值更新为98.5,下列选项中,能够完成上述功能的SQL语句是 A: UPDATE student set name=’youjun’ grade=98.5 where id=1; B: UPDATE student set name=’youjun’, grade=98.5 where id=1; C: UPDATE FROM student set name=’youjun’ ,grade=98.5 where id=1; D: UPDATE student Values name=’youjun’ grade=98.5 where id=1;

    • 3

      MYSQL中,可以使用_________语句来为指定数据库添加用户 A: set user B: create user C: update user D: drop user

    • 4

      把student表中id字段值小于3的记录,将这些记录的grade字段值都更新为100() A: UPDATE FROM student SET grade=100 where id<;3 B: UPDATE student SET grade=100 where id<;3 C: UPDATE student SET grade=100 D: UPDATE INTO student SET grade=100 where id<;3