如何在MySQL中执行条件GROUP BY来获取？
让我们首先创建一个表-
mysql> create table DemoTable ( StudentName varchar(40), StudentMarks int );
使用插入命令在表中插入一些记录-
mysql> insert into DemoTable values('John',78);
mysql> insert into DemoTable values('Chris',48);
mysql> insert into DemoTable values('John',67);
mysql> insert into DemoTable values('Chris',89);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。在这里，我们有一些重复的学生姓名，例如带有标记78和67的学生“约翰”-
+-------------+--------------+ | StudentName | StudentMarks | +-------------+--------------+ | John | 78 | | Chris | 48 | | John | 67 | | Chris | 89 | +-------------+--------------+ 4 rows in set (0.00 sec)
以下是执行条件GROUPBY并显示带有最高分的唯一学生姓名的查询。例如，学生“约翰”的最高分数为78-
mysql> select StudentName,Max(StudentMarks) AS StudentMarks from DemoTable group by StudentName;
这将产生以下输出-
+-------------+--------------+ | StudentName | StudentMarks | +-------------+--------------+ | John | 78 | | Chris | 89 | +-------------+--------------+ 2 rows in set (0.00 sec)