PostgreSQL: how to combine multiple rows?

Question

I have a table like this to save the results of a medical checkup and the date of the report sent and the result. Actually the date sent is based on the clinic_visit date. A cli

Answer 1

While I was reading about "simulating row_number", I tried to figure out another way to do this.

SELECT client_id,  
       MAX( CASE seq WHEN 1 THEN result ELSE '' END ) AS result1,  
       MAX( CASE seq WHEN 2 THEN result ELSE '' END ) AS result2,  
       MAX( CASE seq WHEN 3 THEN result ELSE '' END ) AS result3,  
       MAX( CASE seq WHEN 4 THEN result ELSE '' END ) AS result4,  
       MAX( CASE seq WHEN 5 THEN result ELSE '' END ) AS result5  
FROM ( SELECT p1.client_id, 
              p1.result,  
              ( SELECT COUNT(*)  
                FROM labresults p2  
                WHERE p2.client_id = p1.client_id  
                AND p2.result <= p1.result )  
       FROM labresults p1 
) D ( client_id, result, seq )  
GROUP BY client_id;  

but the query took 10 minutes (500,000 ms++). for 30,000 records. This is too long..