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建表 学生表 create table Student(S# varchar(10),Sname nvarchar(10),Sage datetime,Ssex nvarchar(10))DEFAULT charset = utf8; insert into Student values('01' , '赵雷' , '1990-01-01' , '男') insert into Student...

1. 建表时设置默认字符串编码方式为utf8 create table test() default charset = utf8; 2. 已经添加的表需要设置一下： alter table test convert to character set utf8 collate utf8_unicode_ci; 3. 直接修改数据库的字符串编码...

在员工工资表中返回第二高的记录，如果没有则返回null。 使用limit offset SELECT (SELECT DISTINCT Salary FROM Employee ORDER BY Salary DESC LIMIT 1 OFFSET 1) AS SecondHighestS...

select Email from ( select Email, count(Email) as num from Person group by Email ) as statistic where num > 1 ; group by 和 having select Email from Person group by Email having count(Emai...