Implementing a total order ranking in PostgreSQL 8.3

Question

The issue with 8.3 is.....rank is introduced in 8.4.

consider the numbers [10,6,6,2]

I wish to achieve a rank of those numbers where the rank is equal to the th

Answer 1

There's a method using an array that works with PG 8.3. It's probably not very efficient, performance-wise, but will do OK if there aren't a lot of values.

The idea is to sort the values in a temporary array, then extract the bounds of the array, then join that with generate_series to extract the values one by one, the index into the array being the row number.

Sample query assuming the table is scores(value int):

SELECT i AS row_number,arr[i] AS score
 FROM (SELECT arr,generate_series(1,nb) AS i
   FROM (SELECT arr,array_upper(arr,1) AS nb
     FROM (SELECT array(SELECT value FROM scores ORDER BY value DESC) AS arr
     ) AS s2
   ) AS s1
 ) AS s0