[英]Select column of the Max(value)
我有這些桌子
記錄:
+----+-------------+--------------+-------------------------+---------+
| Id | IdHealtcare | ValueMonitor | DateMonitor | Checked |
+----+-------------+--------------+-------------------------+---------+
| 1 | 1 | 80 | 2020-05-14 19:40:11.873 | NULL |
| 2 | 2 | 66 | 2020-05-14 20:56:33.360 | NULL |
| 3 | 1 | 100 | 2020-05-14 20:32:24.397 | NULL |
| 4 | 3 | 87 | 2020-05-14 20:57:12.390 | NULL |
+----+-------------+--------------+-------------------------+---------+
衛生保健:
+----+-----------+----------+--------+------------+
| Id | IdPatient | IdDoctor | IdType | RangeValue |
+----+-----------+----------+--------+------------+
| 1 | 1 | 1 | 1 | 0-180 |
| 2 | 1 | 1 | 2 | 50-200 |
| 3 | 2 | 2 | 1 | 90-180 |
+----+-----------+----------+--------+------------+
我想為每種患者的醫療保健類型 select 提供患者的 ID 和最近的日期值。
我已經嘗試過這些查詢:
select p.CodiceFiscale, p.Surname, p.Name, t.Name, Max(r.DateMonitor),
r.ValueMonitor
from dbo.Patients as p
inner join dbo.HealtcareMonitoring as m on m.IdPatient = p.Id
inner join dbo.Records as r on r.IdHealtcare = m.Id
inner join dbo.MonitoringTypes as t on t.Id = m.IdType
where m.IdDoctor = 1
group by t.Name, p.CodiceFiscale, p.Surname, p.Name
SELECT m.IdPatient, m.IdType, MAX(r.DateMonitor), r.ValueMonitor AS LastDate
FROM dbo.Records as r
inner join dbo.HealtcareMonitoring as m on m.Id = r.IdHealtcare
where m.IdDoctor = 1
GROUP BY m.IdPatient, m.IdType
但我不能 select 該值,因為它不包含在聚合 function 或“分組依據”子句中。
我該如何解決? 有沒有更好的方法來解決這個問題?
你為什么不在group by
中添加r.ValueMonitor
? 它應該修復該錯誤
SELECT m.IdPatient, m.IdType, MAX(r.DateMonitor), r.ValueMonitor AS LastDate
FROM dbo.Records as r inner join dbo.HealtcareMonitoring as m
on m.Id = r.IdHealtcare
where m.IdDoctor = 1
GROUP BY m.IdPatient, m.IdType, r.ValueMonitor
一種解決方案可以按非聚合列分組
select p.CodiceFiscale, p.Surname, p.Name, t.Name, Max(r.DateMonitor), r.ValueMonitor from dbo.Patients as p
inner join dbo.HealtcareMonitoring as m
on m.IdPatient = p.Id
inner join dbo.Records as r
on r.IdHealtcare = m.Id
inner join dbo.MonitoringTypes as t
on t.Id = m.IdType
where m.IdDoctor = 1 group by t.Name, p.CodiceFiscale, p.Surname, p.Name
group by p.CodiceFiscale, p.Surname, p.Name, t.Name, r.ValueMonitor
另一種解決方案可能是使用子查詢,但性能更差
select p.CodiceFiscale, p.Surname, p.Name, t.Name,
(select MAX(DateMonitor) from dbo.Records where IdHealtcare = m.Id)
, r.ValueMonitor from dbo.Patients as p
inner join dbo.HealtcareMonitoring as m
on m.IdPatient = p.Id
inner join dbo.MonitoringTypes as t
on t.Id = m.IdType
where m.IdDoctor = 1 group by t.Name, p.CodiceFiscale, p.Surname, p.Name
更多關於加入與子查詢的性能在這里SQL 加入與 SQL 子查詢(性能)?
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