Re: generate_series with left join

On Wed, 2006-06-28 at 13:34 -0500, Aaron Bono wrote:

> select
> year_list.year,
> count(one.*),
> count(two.*)
> from (
> select years
> from generate_series(2006,2009) as years
> ) year_list
> left outer join mytable as one on (
> date_part('year', one.date) = year_list.years
> and one.cause = 1
> )
> left outer join mytable as two on (
> date_part('year', two.date) = year_list.years
> and two.cause = 2
> )
> group by
> year_list.year
> ;
>
>
> select
> year_list.year,
> mytable.cause,
> count(mytable.*)
> from (
> select years
> from generate_series(2006,2009) as years
> ) year_list
> left outer join mytable on (
> date_part('year', mytable.date) = year_list.years
> )
> group by
> year_list.year,
> mytable.cause
> ;
>
Aaron,
Thank you so much for your reply.
However, the 2 examples you provided have "weird" outputs:

The first:
years | count | count
-------+---------+---------
2009 | 0 | 0
2008 | 0 | 0
2007 | 0 | 0
2006 | 7802080 | 7802080
(4 rows)

Time: 87110.753 ms << yay.

The second:

years | cause | count
-------+---------+-------
2009 | | 0
2008 | | 0
2007 | | 0
2006 | 6 | 1
2006 | 1 | 4030
2006 | 2 | 1936
2006 | 3 | 4078
2006 | 100 | 3159
2006 | 98 | 2659
2006 | 99 | 2549

My need is really to only group the counts of where cause=1 and cause=2
for each year, none of the others.

> I think one of the problems many people have is the writing of their
> SQL in paragraph form. It makes the SQL really hard to read and even
> harder to understand and debug. Formatting your SQL like I did above
> may make it easier to see what is wrong.

Indeed. Note taken, i'll improve my formatting.

\\pb

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