如何计算每个病人预订多少医生？

本文介绍了如何计算每个病人预订多少医生？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 我需要的结果如下： PatientID医生 Patient1 3 Patient2 2 Patient3 1 预订的表格如下 GPS表 PatientID DoctorID DATE Patient1医生1 2016-02-16 Patient1医生1 2016-04-08 Patient1 Doctor2 2016-06-09 Patient2 Doctor3 2017-01-02 Patient2 Doctor6 2016-12-01 Patient3 Doctor1 2016-07-12 还有更多的预订，但我只是给这个表作为例子。 如果这个人为医生预订了2次，我还需要确保它不会算同一个医生。 我现在的代码是： 选择Bookings.PatientID，count（Bookings.DoctorID）as Book from Bookings where Bookings.DoctorID;感谢您的帮助！ 选择患者，计数（*）从（选择不同的Bookings.PatientID作为患者，DoctorID作为医生从预订）作为t 由患者分组; I need the results to look like:PatientID DoctorsPatient1 3Patient2 2Patient3 1The booked table looks like thisGPS TablePatientID DoctorID DATEPatient1 Doctor1 2016-02-16Patient1 Doctor1 2016-04-08Patient1 Doctor2 2016-06-09Patient2 Doctor3 2017-01-02Patient2 Doctor6 2016-12-01Patient3 Doctor1 2016-07-12There are more bookings, but I am just giving this table as an example.Also I need to make sure that it would not count the same doctor if the person is booked 2 times for the doctor.The code I have right now is:select Bookings.PatientID, count(Bookings.DoctorID) as Doctors from Bookings where Bookings.DoctorID;Thank you for any help! 解决方案 Use Group by over a temp table with distinct patient and doctor select Patient, count(*) from ( select distinct Bookings.PatientID as Patient ,DoctorID as Doctors from Bookings ) as t Group by Patient; 这篇关于如何计算每个病人预订多少医生？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！