在MySQL中为具有mark1和mark2记录的学生获取最大的个人分数？
为此，请MAX()与GROUPBY子句一起使用。让我们首先创建一个表-
mysql> create table DemoTable -> ( -> StudentEmailId varchar(20), -> Marks1 int, -> Marks2 int -> );
使用插入命令在表中插入一些记录-
mysql> insert into DemoTable values('John@gmail.com',45,32);
mysql> insert into DemoTable values('John@gmail.com',32,45);
mysql> insert into DemoTable values('Carol@gmail.com',32,45);
mysql> insert into DemoTable values('David@gmail.com',45,32);使用select语句显示表中的所有记录-
mysql> select *from DemoTable ;
这将产生以下输出-
+-----------------+--------+--------+ | StudentEmailId | Marks1 | Marks2 | +-----------------+--------+--------+ | John@gmail.com | 45 | 32 | | John@gmail.com | 32 | 45 | | Carol@gmail.com | 32 | 45 | | David@gmail.com | 45 | 32 | +-----------------+--------+--------+ 4 rows in set (0.00 sec)
这是查询以获取具有标记1和标记2记录的学生的最大单个标记的查询-
mysql> select StudentEmailId,max(Marks1),max(Marks2) from DemoTable -> group by StudentEmailId;
这将产生以下输出-
+-----------------+-------------+-------------+ | StudentEmailId | max(Marks1) | max(Marks2) | +-----------------+-------------+-------------+ | John@gmail.com | 45 | 45 | | Carol@gmail.com | 32 | 45 | | David@gmail.com | 45 | 32 | +-----------------+-------------+-------------+ 3 rows in set (0.00 sec)