Alternately, you could have a gdp table and a fish_catch table which
would be easily joined to give the same result.
Expanding on this:
create table fish_catches (country text not null,
data_year date not null,
primary key (country, data_year),
fish_catch numeric not null);
create table gdp (country text not null reference countries
data_year date not null,
primary key (country, data_year),
gdp numeric not null);
This makes your queries quite simple:
select country, data_year, fish_catch, gdp
from fish_catches
natural join gdp
where country = :country
order by data_year
limit 1;
Hmmm..... Don't really get that query working. My SQL looks like this
now:
SELECT
id_country,
year,
value
FROM
internet_users
NATURAL JOIN
gdp
WHERE
id_country = 8
ORDER BY
year
LIMIT
1
But there is no result.
My table looks like this (for each variable one table):
id_country year value
4 1980 6.6
4 1981 7.0
...
6 1980 5.1
Thanks for any advice!
Stef
---------------------------(end of broadcast)---------------------------
TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match
