Обсуждение: adding missing FROM-clause

Dear All,

I have a simple join query

SELECT c1 FROM t1
INNER JOIN
t2 ON t2.c2 = t1.c2 WHERE t3.c3= t2.c3;

Which gives the expected result but I get the message
NOTICE:  adding missing FROM-clause entry for table "t3"

How do I get rid of this NOTICE, i.e. how should I construct my select
query.

Many thanks

Colin

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On Friday 29 October 2004 08:42 am, C G wrote:
> Dear All,
>
> I have a simple join query
>
> SELECT c1 FROM t1
> INNER JOIN
> t2 ON t2.c2 = t1.c2 WHERE t3.c3= t2.c3;
                                               ^^^^^
Your join doesn't alias anything as t3
I'd say you get rid of the notice once you replace t3 with t1

>
> Which gives the expected result but I get the message
> NOTICE:  adding missing FROM-clause entry for table "t3"
>
> How do I get rid of this NOTICE, i.e. how should I construct my select
> query.
>
> Many thanks
>
> Colin
>
> _________________________________________________________________
> Want to block unwanted pop-ups? Download the free MSN Toolbar now!
> http://toolbar.msn.co.uk/
>
>
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On Sat, 30 Oct 2004 01:42 am, C G wrote:
> Dear All,
>
> I have a simple join query
>
> SELECT c1 FROM t1
> INNER JOIN
> t2 ON t2.c2 = t1.c2 WHERE t3.c3= t2.c3;
>
Instead
SELECT c1 FROM t2, t1 INNER JOIN t2 ON t2.c2 = t1.c2 WHERE t3.c3=t2.c3

OR

SELECT c1 FROM t1 INNER JOIN t2 ON t2.c2 = t1.c2 JOIN t3 ON t3.c3 = t2.c3

> Which gives the expected result but I get the message
> NOTICE:  adding missing FROM-clause entry for table "t3"
>
> How do I get rid of this NOTICE, i.e. how should I construct my select
> query.
>
> Many thanks
>
> Colin
>
> _________________________________________________________________
> Want to block unwanted pop-ups? Download the free MSN Toolbar now!
> http://toolbar.msn.co.uk/
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 8: explain analyze is your friend
>
>

csgcsg39@hotmail.com ("C G") writes:

> Dear All,
>
> I have a simple join query
>
> SELECT c1 FROM t1
> INNER JOIN
> t2 ON t2.c2 = t1.c2 WHERE t3.c3= t2.c3;
>
> Which gives the expected result but I get the message
> NOTICE:  adding missing FROM-clause entry for table "t3"
>
> How do I get rid of this NOTICE, i.e. how should I construct my select
> query.
>

SELECT c1 FROM t1, t2, t3
   WHERE t2.c2 = t1.c2 AND t3.c3 = t2.c3;

or

SELECT c1 FROM t1
  INNER JOIN t2 ON t2.c2 = t1.c2
  INNER JOIN t3 ON T3.c3 = t2.c3;


The above can also be written as

SELECT c1 FROM t1
   JOIN t2 USING(c2)
   JOIN t3 USING(c3);

or even
SELECT c1 FROM t1
  NATURAL JOIN t2
  NATURAL JOIN t3;

This last might be problematic if t3 has a column named c1.


Question:

Is there any advantage to specifying USING() rather than ON?  I know
that if I do SELECT * from T1 JOIN t2 USING(col) then I only get 1
instance of col in the returned rows, but I'm wondering if there is
any advantage to the planner by specifying either USING() or ON?


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