I am running the Postgres(8.2.11) on Windows.
I have 2 tables, one with users and one with locations.
user_table
---------------
user_id user_code price value
1 22222 45.23 -97.82
2 33333 42.67 -98.32
3 44444 35.56 -76.32
locations
--------------
id code price value
1 22222 45.23 -97.82
2 33333 42.67 -98.32
3 44444 43.26 -98.65
I have a query that takes every user and looks into locations to see if the
code, price and value match up. If they do then count it.
select count(*)
from user_table u, locations l
where u.user_code = l.code
and u.price = l.price
and u.value = l.value;
The answer to this should be 2, but when I run my query I get 4 (in fact
more entries than user_table) which is incorrect. What am I doing
incorrectly? I have been breaking my head over this for a while. Is there
some other query to get the required results? Any help would be highly
appreciated. I gave a simple example above, but the query runs over 2 tables
with about a million entries in each. So I am unable to verify what is
wrong, but I know the count is incorrect as I should not have more than what
is in the user_table.
Thanks,
Michael
