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mysqlsqlclause

Show only the most recent givendate for each record in MySQL

I have the table below with the Patientid, the vaccine name that they received, and the date they received it. I am trying to write an SQL query to only show the most recent given date for each patient.

patientId   vaccinename  givenDate
100          Influenza   7/23/2013
100          Influenza   10/14/2014
101          Influenza   11/24/2009
101          Influenza   10/14/2013
101          Influenza   10/22/2014
102          Influenza   10/24/2013
102          Influenza   10/8/2014
Solution

  • Pretty straightforward, just group by the patient and vaccine and return the max date for the most recent.

    SELECT patientID, vaccinename, MAX(givenDate)
FROM patient_info
GROUP BY patientID, vaccinename

    SQL Fiddle: http://sqlfiddle.com/#!2/c6eee9/1