Joining multiple tables on one join statement?

Question

Is it possible to do the following join?

Select *
From table1
Inner join table2 on table1.pk = table2.fk
Inner join table3 on table2.pk = table3.fk and table1.pk = table3.fk

Normally I have only use two tables in one join statement. The last statement has three tables.

Should be the same: `Select * From table1 Inner join table2 on table1.pk = table2.fk Inner join table 3 on table2.pk = table3.fk WHERE table1.pk = table3.fk` — Christian, May 28 '15 at 10:43
Yes it is possible, but here `and table1.pk = table3.fk` is redundant. — Giorgi Nakeuri, May 28 '15 at 10:49
@GiorgiNakeuri, note, it's different columns, so we don't know if it's reduntant or not. — jarlh, May 28 '15 at 11:01
If you have requirement like this, then it is definitely possible. — ram_sql, May 29 '15 at 09:00

Ilessa · Accepted Answer · 2015-05-28T12:18:28.897

3

Just do:

SELECT *
FROM table1
INNER JOIN table2 
   ON table1.pk = table2.fk
INNER JOIN table3 
   ON table1.pk = table3.fk
   AND table2.pk = table3.fk

Side note

In theory you can join to as many tables as you like - just be aware that the more tables you join to, the more the performance will be impacted negatively.

At that point it's better to think carefully about the query you are constructing and consider breaking it down into smaller queries as these will be more efficient.

edited May 28 '15 at 12:18

answered May 28 '15 at 11:02

Ilessa

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Note, it's different columns, so table1 join table3 is needed! – jarlh May 28 '15 at 11:07

Joining multiple tables on one join statement?

1 Answers1

Side note