在 MySQL 中选择聚合函数和所有其他列
mysqlmysqli database
首先我们创建一个表 −
mysql> create table DemoTable1621 -> ( -> StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> StudentName varchar(20), -> StudentMarks int -> ); Query OK, 0 rows affected (1.69 sec)
使用 insert 命令在表中插入一些记录 −
mysql> insert into DemoTable1621(StudentName,StudentMarks) values('Chris',45);
Query OK, 1 row affected (0.22 sec)
mysql> insert into DemoTable1621(StudentName,StudentMarks) values('Bob',78);
Query OK, 1 row affected (0.13 sec)
mysql> insert into DemoTable1621(StudentName,StudentMarks) values('David',89);
Query OK, 1 row affected (0.16 sec)
mysql> insert into DemoTable1621(StudentName,StudentMarks) values('Adam',87);
Query OK, 1 row affected (0.20 sec)
使用 select 语句显示表中的所有记录 −
mysql> select * from DemoTable1621;
这将产生以下输出 −
+-----------+-------------+--------------+ | StudentId | StudentName | StudentMarks | +-----------+-------------+--------------+ | 1 | Chris | 45 | | 2 | Bob | 78 | | 3 | David | 89 | | 4 | Adam | 87 | +-----------+-------------+--------------+ 4 rows in set (0.00 sec)
以下是选择聚合函数的查询 −
mysql> select tblData.*,( select max(StudentMarks) from DemoTable1621) as MaximumMarks from DemoTable1621 tblData;
这将产生以下输出 −
+-----------+-------------+--------------+--------------+ | StudentId | StudentName | StudentMarks | MaximumMarks | +-----------+-------------+--------------+--------------+ | 1 | Chris | 45 | 89 | | 2 | Bob | 78 | 89 | | 3 | David | 89 | 89 | | 4 | Adam | 87 | 89 | +-----------+-------------+--------------+--------------+ 4 rows in set (0.00 sec)
