Suppose I have the 'abc' table:

individual year  size
1_4_5      1     112
1_4_5      2     123
1_4_5      3     146
1_4_5      4     157
2_8_3      1     92
2_8_3      2     104
2_8_3      3     98
...

I want to pivot the table to get:

individual size_yr1   size_yr2   size_yr3   ...
1_4_5      112        123        146
2_8_3      92         104        98
...

In Access, you would do:

TRANSFORM Avg(size) AS size_avg
SELECT abc.individual
FROM abc
GROUP BY abc.individual
PIVOT abc.year;

But this is MS-specific SQL...

Is there a simple way to do it in PostgreSQL?

You can use a function called "crosstab" to do that.
It is part of the PostgreSQL contrib-section and it has to be installed separately. Checkout the "contrib/tablefunc" directory inside your sourceball.

Hans-Jürgen Schönig
Cybertec Schönig & Schönig GmbH
URL: http://www.postgresql-support.de
PostgreSQL Support, Training, Replication