MySQL selecting from multiple tables

Question

im trying to select data from multiple tables, now i am fine with doing it with two tables as i do a query like so:

$myquery = sql_query(
    "SELECT a.object_title, a.published_by, b.userid
     FROM table1 AS a 
     JOIN table2 AS b ON (a.published_by = b.userid)"
);

But see now, i want to select data from a third table, however this third table does not have relationship such as primary key between the first two tables, so i simply want to just pull data from it and form any sort of link with a "JOIN".

How would simply add the third to this query?

Thanks

Write a seperate query? Since it's not related, you don't need to write it in the above query. — davey
– davey, Commented Apr 7, 2014 at 8:32
I cant do this, as it will overwrite my first query as i need them both in the same section. — user3332590
– user3332590, Commented Apr 7, 2014 at 8:34
You could simply do this: SELECT a.object_title, a.published_by, b.userid, c.id, c.field FROM table1 AS a, table3 as c Just keep in mind that this will preform a Cartesian product with this table. — Fadey
– Fadey, Commented Apr 7, 2014 at 8:37
You should also have a look at this Q&A that I wrote which covers a lot of this sort of thing in detail. — Fluffeh
– Fluffeh, Commented Apr 23, 2014 at 11:46

Community · Accepted Answer · 2017-05-23 12:23:34Z

2

You could use CROSS JOIN :

$myquery = sql_query(
    "SELECT a.object_title, a.published_by, b.userid, c.whatever
     FROM table1 AS a 
     JOIN table2 AS b ON (a.published_by = b.userid)
     CROSS JOIN table3 AS c"
);

I used this other post to find the idea.

More infos here.

edited May 23, 2017 at 12:23

CommunityBot

11 silver badge

answered Apr 7, 2014 at 8:35

Theox

1,3639 silver badges20 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Matthew Thomas · Accepted Answer · 2014-04-07 08:36:32Z

0

Add within you query a Left Join.

answered Apr 7, 2014 at 8:36

Matthew Thomas

362 bronze badges

Comments

halfer · Accepted Answer · 2014-04-23 11:31:10Z

0

$myquery = sql_query(
            "SELECT a.object_title, a.published_by, b.userid, c.column_name
             FROM Table1 AS a 
             JOIN Table2 AS b ON (a.published_by = b.userid)
             CROSS JOIN Table3 AS c"
);

edited Apr 23, 2014 at 11:31

halfer

20.2k20 gold badges110 silver badges207 bronze badges

answered Apr 7, 2014 at 10:27

Mayuri

4326 silver badges13 bronze badges

Collectives™ on Stack Overflow

MySQL selecting from multiple tables

3 Answers 3

Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related