sql - Time overlaps from Nesting queries

Question

Based on the current schema I have been asked to find

-- people who were untested and exposed to some one infectious -- Do not list anyone twice and do not list known sick people -- Exposed = at the same place, and overlap in time (No overlap time needed for simplicity)

From the query below I find my answer except I cannot remove the people who are 'postive' because the second part my query i.e the time lapse depends on the first part i.e the time the positive people went to the same locations.

select * from (
select DISTINCT person.PersonID, Register.LocID, Register.Checkin, Register.CheckOut
from person 
join Register on Person.PersonID = Register.PersonID 
join testing on person.PersonID  = testing.PersonID
where testing.Results is 'Positive' ) a 
join (
SELECT DISTINCT Person.PersonID, Register.LocID , Register.Checkin, Register.CheckOut
from person join Register on Person.PersonID = Register.PersonID 
where person.PersonID  
not in (SELECT DISTINCT testing.PersonID from testing)) b on a.LocID = b.LocID 
and b.checkin >= a.CheckIn and b.CheckIn <= a.CheckOut

So my question is, What modification does this query need to show the results of the results of the second part only?

I consider the first part to be

select * from (
select DISTINCT person.PersonID, Register.LocID, Register.Checkin, Register.CheckOut
from person 
join Register on Person.PersonID = Register.PersonID 
join testing on person.PersonID  = testing.PersonID
where testing.Results is 'Positive' ) a

And the second part to be

join (
SELECT DISTINCT Person.PersonID, Register.LocID , Register.Checkin, Register.CheckOut
from person join Register on Person.PersonID = Register.PersonID 
where person.PersonID  
not in (SELECT DISTINCT testing.PersonID from testing)) b on a.LocID = b.LocID 
and b.checkin >= a.CheckIn and b.CheckIn <= a.CheckOut

score 1 · Accepted Answer

为了便于阅读，您可以CTE像这样创建 s：

with
  -- returns all the untested persons
  untested as (select p.* from person p left join testing t on t.personid = p.personid where t.testingid is null), 
  --  returns all the infected persons
  infected as (select * from testing where results = 'Positive'),
  -- returns all the locids that infected persons visited and the start and dates of these visits
  loc_positive as (
    select r.locid, i.timestamp startdate, r.checkout enddate 
    from register r inner join infected i 
    on i.personid = r.personid and i.timestamp between r.checkin and r.checkout
  )
-- returns the distinct untested persons that visited the same locids with persons tested positive at the same time after they were tested 
select distinct u.*
from untested u 
inner join register r on r.personid = u.personid
inner join loc_positive lp on lp.locid = r.locid 
where lp.startdate <= r.checkout and lp.enddate >= r.checkin

score 1 · Accepted Answer

这是一个复杂的查询。因为你不想要重复，我建议exists只使用外部查询persons。

让人们同时在同一个地方的想法是register使用位置和时间重叠的自我加入。我认为这是查询中最复杂的部分。剩下的就是检查一个人是否积极：

select p.*
from person p 
where not exists (select 1
                  from testing t
                  where t.personid = p.personId and t.results = 'positive'
                 ) and
      exists (select 1
              from register r1 join
                   register r2
                   on r1.locid = r2.locid and
                      r1.checkin < r2.checkout and
                      r2.checkout > r1.checkin join
                   testing t2
                   on r2.personid = t2.personid and
                      t2.results = 'positive' and
                      t2.timestamp < r2.checkout
              where r1.personid = p.personid
             );

时机有点棘手，但我认为时机是有道理的。有人需要在他们在同一个地方之前测试呈阳性。当然，t2.timestamp < r2.checkout如果没有时序约束，你可以去掉。

score 0 · Accepted Answer

这个答案的解决方案是在第一行的星号上添加一个不同的列名。

select DISTINCT unt.PersonID from (
select  person.PersonID, Register.LocID, Register.Checkin, Register.CheckOut
from person join Register on Person.PersonID = Register.PersonID join testing on person.PersonID  = testing.PersonID
where testing.Results is 'Positive' ) pos
join (
SELECT Person.PersonID, Register.LocID , Register.Checkin, Register.CheckOut
from person join Register on Person.PersonID = Register.PersonID where person.PersonID  
not in (SELECT  testing.PersonID from testing)) unt on pos.LocID = unt.LocID 
and unt.checkin >= pos.CheckIn and unt.CheckIn <= pos.CheckOut;

sql - Time overlaps from Nesting queries

3 回答 3

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