[GENERAL] left outer join on multi tables

[quickcur]

Hi, here are my tables

table name
{
   id integer primary key
   first_name text,
   middle_name text,
   last_name text
}

table address
{
   id integer primary key
   number int,
   street text,
   city text,
   state text
}

table work
{
   id integer primary key
   hours text,
   shift
}

table person
{
id integer primary key
namid integer references name(id),
addressid integer referenes address(id),
workid integer references work(id)
}
nameid, addressid or workid in person table may be empty.

I would like to make a view which shows all information about a person
in one row

first_name, last_name, street, city, workhours, ...

In the peron table, if  the workid, addressid, or nameid is empty, just
do not display the correspodent information.

I think I need left outer join, but I do not know how to use it. Could
anyone help?

Thanks,

qq


---(end of broadcast)---
TIP 2: Don't 'kill -9' the postmaster

[GENERAL] join table with empty fields and default

[quickcur]

Hi, suppose I have two tables

table User
{
id integer,
name text,
address text
}

Table UserWork
{
userid integer references User(id),
work text
}

Suppose I have three users

idnameaddress
1 Tony  main street
2 Peter Big ave
3 Richard  Loop Blvd

And two of them work

UserWork
useridwork
1   programming
3   studying

I would like to join table user and userwork, where if a user has a
work, I list it. If he does not, I give it some default value "no work"

Join User and UserWork
idnameaddress  work
1 Tony  main streetprogramming
2 Peter Big ave  no work
3 Richard  Loop Blvd  studying

How can I write the sql?

Thanks,

qq


---(end of broadcast)---
TIP 3: Have you checked our extensive FAQ?

   http://www.postgresql.org/docs/faq

Re: [GENERAL] join table with empty fields and default

[quickcur]

Thank you for your post. To make things a little bit complicated:

Suppose I have another table UserInformation

UserInfomation
{
userid integer referenes user(id),
 mothername text
}

I would like methername also appear in the final join. Suppose each
user must have a mothername.

Could you please whow me the sql again?

Thanks again,

qq



Michael Fuhr wrote:
> On Sat, Jul 22, 2006 at 12:47:42PM -0700, [EMAIL PROTECTED] wrote:
> > I would like to join table user and userwork, where if a user has a
> > work, I list it. If he does not, I give it some default value "no work"
>
> You could use an outer join and COALESCE.
>
> http://www.postgresql.org/docs/8.1/interactive/tutorial-join.html
> http://www.postgresql.org/docs/8.1/interactive/queries-table-expressions.html#QUERIES-JOIN
> http://www.postgresql.org/docs/8.1/interactive/functions-conditional.html#AEN12639
>
> Example:
>
> SELECT u.id, u.name, u.address, COALESCE(uw.work, 'no work') AS work
> FROM "user" AS u
> LEFT OUTER JOIN userwork AS uw ON uw.userid = u.id;
>
> --
> Michael Fuhr
>
> ---(end of broadcast)---
> TIP 1: if posting/reading through Usenet, please send an appropriate
>subscribe-nomail command to [EMAIL PROTECTED] so that your
>message can get through to the mailing list cleanly


---(end of broadcast)---
TIP 5: don't forget to increase your free space map settings