Hi,
This query:
select c.id_currency,max(p.modified_on) from currency c left join
price_line p using (id_currency) where p.id_line=1 group by
c.id_currency;
doesn't list all c.id_currency's, only those with a price_line. However
this one does:
select c.id_currency,max(p.modified_on) from curren
My first guess is that
NULL fails the condition on your WHERE clause,
p.id_line = 1
So your WHERE clause introduces an additional level of filtering that
filters out the NULLs coming from the LEFT JOIN...
Didn't do any tests, it's just a guess...
Best,
Oliveiros
- Original Message -
> where p.id_line=1
this filters rows after join was applied. Try this
select c.id_currency,max(p.modified_on) from currency c left join
price_line p using (id_currency) where (p.id_line=1 or p.id_line is null) group
by
c.id_currency;
> Hi,
> This query:
> select c.id_currency,max(p.modif
On Fri, Feb 12, 2010 at 11:35:02AM -, Oliveiros C, wrote:
> My first guess is that
> NULL fails the condition on your WHERE clause,
> p.id_line = 1
>
> So your WHERE clause introduces an additional level of filtering
> that filters out the NULLs coming from the LEFT JOIN...
So, if I understan
Yes, because your WHERE is something that comes after the operation
of the LEFT JOIN, in practice, defeating the purpose you intented.
On your second query the p.id_line = 1 doesn't do that because it is part of
the LEFT JOIN itself..
HTH
Best,
Oliveiros d'Azevedo Cristina
- Original Mes
Hi,
Here is my schema:
cruise_line -> ship(id_line) -> cruise_type(id_ship) -> cruise(id_cruise_type)
-> price(id_cruise, id_currency) <- currency (USD,GBP,EUR,CAD)
(a 'cruise' is a 'cruise_type' + a date)
I am trying to display a count of cruise's for each ship and each
currency even
Louis-David Mitterrand wrote:
> Here is my schema:
> cruise_line -> ship(id_line) -> cruise_type(id_ship) -> cruise(id_cruise_type)
> -> price(id_cruise, id_currency) <- currency (USD,GBP,EUR,CAD)
> (a 'cruise' is a 'cruise_type' + a date)
> I am trying to display a count of cruise's for
Hello,
I have 2 tables (A and B) where the table B has a foreign key reference to
table A. Like this:
create table A (x int primary key);
create table B (y int primary key, z int references A (x) );
As you can see, i've not specified any further 'on delete' clause to the
foreign key constraint
Shruthi A wrote:
> I have 2 tables (A and B) where the table B has a foreign key reference to
> table A. Like this:
> create table A (x int primary key);
> create table B (y int primary key, z int references A (x) );
> As you can see, i've not specified any further 'on delete' clause to the
>
