Re: [SQL] problem with join & count

> i need an sql query that will return:
>
> name   |  how_often
> -------------------
>  toto  | 2
>  titi  | 1
>  tutu  | 2
>
> that is, the result table should contain all names present in the first table
> and then the number of times the number associated with the name appears in
> the second table.

    Postgres  does not (and v6.5 will not) support outer joins or
    subselects in the targetlist, what's required to do that in a
    single SQL statement.

    What  you  could  do  is using a SQL function that covers the
    count() like this:

        create function num_refs (int4) returns int4 as '
            select count(*) from tab2 where id = $1;
        ' language 'SQL';

        select item_name, num_refs(id) as how_often from tab1;

    I changed 'number' into id and name  into  item_name  because
    both are reserved words.


Jan

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