计算列中数字的平均值 MySQL 查询?
mysqlmysqli database
借助 MySQL 聚合函数 AVG() 计算列中数字的平均值。
语法如下 −
select avg(yourColumnName) as anyVariableName from yourTableName;
为了理解上述概念，让我们创建一个表。以下是创建表的查询。
mysql> create table AverageCalculateDemo −> ( −> SubjectMarks int −> ); Query OK, 0 rows affected (0.67 sec)
以下是向表中插入一些记录的查询 −
mysql> insert into AverageCalculateDemo values(70); Query OK, 1 row affected (0.14 sec) mysql> insert into AverageCalculateDemo values(80); Query OK, 1 row affected (0.19 sec) mysql> insert into AverageCalculateDemo values(65); Query OK, 1 row affected (0.13 sec) mysql> insert into AverageCalculateDemo values(55); Query OK, 1 row affected (0.13 sec) mysql> insert into AverageCalculateDemo values(60); Query OK, 1 row affected (0.23 sec)
使用 select 语句显示所有值。查询如下，显示所有记录 −
mysql> select *from AverageCalculateDemo;
以下是输出 −
+--------------+ | SubjectMarks | +--------------+ | 70 | | 80 | | 65 | | 55 | | 60 | +--------------+ 5 rows in set (0.00 sec)
这是在 MySQL 中计算列平均值的查询 −
mysql> select avg(SubjectMarks) as AverageOf4Numbers from AverageCalculateDemo;
以下是显示平均值的输出 −
+-------------------+ | AverageOf4Numbers | +-------------------+ | 66.0000 | +-------------------+ 1 row in set (0.00 sec)
