mySQL 排除计数列(如果低于)

Question

我正在尝试查找每种类型所有者的工作时间总和，不包括经验级别为“初级”的员工以及任何少于 3 名成员的经验级别类型的员工的服务。我一直在研究这个问题，但无法得到答案......

表格:

OWNER ( OwnerID, OwnerName, OwnerEmail, OwnerType )
PROPERTY ( PropertyID, PropertyName, Street, City, State, Zip, OwnerID )
EMPLOYEE ( EmployeeID, LastName, FirstName, CellPhone, ExperienceLevel )
SERVICE ( PropertyID, EmployeeID, ServiceDate, HoursWorked )

我最新的查询:

SELECT OwnerType, SUM(HoursWorked) AS SumOfHoursWorked
 FROM EMPLOYEE, SERVICE, OWNER
 WHERE EMPLOYEE.EmployeeID = SERVICE.EmployeeID 
 AND EMPLOYEE.ExperienceLevel <> 'Junior'
 AND (SELECT COUNT(ExperienceLevel) > 2)

Answer 1

select 语句中的所有表之间都需要有联接条件，并且您仅限定员工和服务之间的联接。

除了

where employee.employeeid = service.employeeid 

添加

and service.propertyid = property.propertyId 
and property.ownerid = owner.ownerid  

正如 Mihai 的评论所建议的

and employee.experiencelevel in (select experiencelevel from employee having count(*) > 2)

最后，如果对值进行分组，求和效果会更好。

group by ownertype;