解决错误1111(HY000)：在MySQL中无效使用组函数？如何正确使用带有where子句的聚合函数？
为了在MySQL中的where子句中正确使用聚合函数，以下是语法-
select *from yourTableName where yourColumnName > (select AVG(yourColumnName) from yourTableName);
为了理解上述概念，让我们创建一个表。创建表的查询如下-
mysql> create table EmployeeInformation -> ( -> EmployeeId int, -> EmployeeName varchar(20), -> EmployeeSalary int, -> EmployeeDateOfBirth datetime -> );
现在，您可以使用insert命令在表中插入一些记录。查询如下-
mysql> insert into EmployeeInformation values(101,'John',5510,'1995-01-21'); mysql> insert into EmployeeInformation values(102,'Carol',5600,'1992-03-25'); mysql> insert into EmployeeInformation values(103,'Mike',5680,'1991-12-25'); mysql> insert into EmployeeInformation values(104,'David',6000,'1991-12-25'); mysql> insert into EmployeeInformation values(105,'Bob',7500,'1993-11-26');
使用select语句显示表中的所有记录。查询如下-
mysql> select *from EmployeeInformation;
以下是输出-
+------------+--------------+----------------+---------------------+ | EmployeeId | EmployeeName | EmployeeSalary | EmployeeDateOfBirth | +------------+--------------+----------------+---------------------+ | 101 | John | 5510 | 1995-01-21 00:00:00 | | 102 | Carol | 5600 | 1992-03-25 00:00:00 | | 103 | Mike | 5680 | 1991-12-25 00:00:00 | | 104 | David | 6000 | 1991-12-25 00:00:00 | | 105 | Bob | 7500 | 1993-11-26 00:00:00 | +------------+--------------+----------------+---------------------+ 5 rows in set (0.00 sec)
这是将聚合与where子句一起使用的正确方法。查询如下-
mysql> select *from EmployeeInformation -> where EmployeeSalary > (select AVG(EmployeeSalary) from EmployeeInformation);
以下是输出-
+------------+--------------+----------------+---------------------+ | EmployeeId | EmployeeName | EmployeeSalary | EmployeeDateOfBirth | +------------+--------------+----------------+---------------------+ | 105 | Bob | 7500 | 1993-11-26 00:00:00 | +------------+--------------+----------------+---------------------+ 1 row in set (0.04 sec)