SELECT concept_name AS drug_name
     , drug_concept_id
     , COUNT(*) AS patient_count
     , MIN ( age ) AS min
     , PERCENTILE_DISC(0.25) WITHIN GROUP( ORDER BY age ) 
                                     AS percentile_25
     , ROUND ( AVG ( age ), 2 ) AS mean     , PERCENTILE_DISC(0.5)  WITHIN GROUP (ORDER BY age )
                                     AS median
     , PERCENTILE_DISC(0.75) WITHIN GROUP (ORDER BY age )
                                     AS percentile_75
     , MAX ( age ) AS max
     , ROUND ( STDDEV ( age ), 1 ) AS stdDev
  FROM /* person, first drug exposure date */
     ( SELECT drug_concept_id
            , person_id
            , EXTRACT( YEAR FROM MIN( drug_exposure_start_date ) ) - year_of_birth 
              AS age
         FROM drug_exposure
         JOIN person USING( person_id )
        WHERE drug_concept_id
           IN /* crestor 20 and 40 mg tablets */
            ( 40165254, 40165258 )
        GROUP BY drug_concept_id, person_id
            , year_of_birth
     )
  JOIN vocabulary.concept ON concept_id = drug_concept_id
 GROUP BY concept_name, drug_concept_id;