Secondary Joins?

Anon

Hi,

I know how to join the primary fields between to tables.. (table1 to table2)

what I need to do is join another field (it needs to be indexed ...yes?) on table1 to one on table3 ...

Can I buy a clue?

Fritz

tomhath

No, doesn't need to be indexed. An index might speed it up if there are more than a few thousand row, that's all.

select whatever
from table1
inner join table2
on table1.id = table2.t1id
inner join table3
on table1.id = table3.t1id

Anon

Thanks tom,

this is STILL making me nuts... Basically I am just trying to join two fields with the same name on two different tables. the fields I am trying to join are not primary keys... Is that a problem?

This query works..

$sql = "SELECT *
from groups
WHERE ($id=g_id) "; //I'm passing a veriable

Yet if I try to do ANY joins I 'can't exitcute query"

This errors...

inner join countries on groups.ctst = countries.ctst

NOTE: I am not joining any primary fields.
NOTE2: Are 'groups' or 'countries' illegal names for sql tables????

[deleted]

Probably because inner is not supported (and not required either)

SELECT whatever
FROM table1, table2, table3
WHERE table1.fielda = table2.fieldb
AND table3.fieldc = table1.fieldy;

fielda and fieldb can be anything, indexed/nonindexed, PK/non-PK, anything.

Just remember that there must be a link in the where clause that links all tables together somehow.
You can JOIN 34 tables, but you must be able to 'walk' across the JOINs from the first table to every other table.

A forum, a FAQ, what else do you need?

Time to YAPF!: http://www.hvt-automation.nl/yapf/

Anon

thanks Vincent... This sort of works, yet I can't add to the varibles

$numresults=mysql_query

(" SELECT ctst
FROM groups, countries WHERE groups.ctst = countries.ctst
");

Errors YET when I do a SELECT * it doesn't...

Fritz

tomhath

Since you have the same column name in two tables, you have to qualify it so the dbms knows which you want:

(" SELECT groups.ctst
FROM groups, countries WHERE groups.ctst = countries.ctst
");