Message-ID: <46AA41EC.8050101@consumercontact.com>
Date: Fri, 27 Jul 2007 15:05:16 -0400
From: Carol Cheung <cacheung@consumercontact.com>
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To: pgsql-sql@postgresql.org
Subject: group by range of values
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Hello,

Here's my table:

db=# select * from tester order by birth_year;
  birth_year | salary
------------+--------
        1946 |  78000
        1949 |  61000
        1951 |  58000
        1953 |  56000
        1958 |  52000
        1962 |  50000
        1965 |  45000
        1967 |  60000
        1968 |  57000
        1970 |  47000
        1972 |  32000
        1973 |  42000
(12 rows)

How can I display the average salary grouped by decade of birth year?
That is, is it possible to display the average salary of those born in 
the 1940's, the average salary of those born in the 1950's, average 
salary of those born in the 1960's, and those born in the 1970's, all in 
one result table?
Something like:

decade | average(salary)
-------+-----------------
   1940 |  69500
   1950 |  53333.33
   1960 |  53000
   1970 |  40333.33

Thanks in advance,
C