Question

In SQL Server 2005 I have a table that stores incoming and outgoing patients in a hospital.

Table data stores are: patient’s full name, date of admission, date of discharge, and the cause of the entrance to the hospital.

What I need is a query to show me the number of patients discharged and re-enter within 72 hours for the same cause.

the table structure is:

CREATE TABLE hospital(
     patient   varchar(50),    
     in        datetime, 
     out       datetime, 
     reason_id int
 );

This is the query:

SELECT DISTINCT H1.PATIENT 
FROM HOSPITAL H1 
   INNER JOIN (SELECT * FROM HOSPITAL) H2 ON DATEDIFF(HOUR,H1.IN,H2.OUT) < 72

Answer 1

select distinct h1.patient
from   Hospital h1 join Hospital h2 on h1.patient = h2.patient
where  h1.[in] < h2.[in]
and    h2.[in] < dateadd(hour, 72, h1.[out])
and    h1.reason_id = h2.reason_id