Re: joining tables

Let me step back a bit, as I realize upon further reflection that the first method will not work.

As far as the issue about two “Ted” records, read it as though I said two “Ted D” records. It refers to two records in the same table with the same key value. If “Ted D” appeared twice in table 1 and twice in table 2, the join would give four resulting records (all combinations of the records from table 1 and the records from table 2 (and the records from table 3) — that’s fundamentally how a join works. If you don’t want that, then make sure that there are no duplicates within each of the tables.

> On Sep 3, 2019, at 9:35 AM, TedJones <[email protected]> wrote:
> 
> Hi Jack
> 
> I'm not sure if I understand your comment about two 'Ted' fields and
> duplication of rows. In the example below there is 'Ted' twice in Table3 1
> and 3 and must appear twice as I've shown in the result as the data in the
> rest of the row is different. I agree with no duplication of rows if all of
> the row is the same.
> 
> Ted
> 
> Table: 1				
> Author	Title	Sales	Publication Date		
> Jim	A	aa	I			
> Ted	B	bb	J		
> Dave	C	cc	K			
> Ted	D	dd	L			
> 
> Table: 2
> Author	Publisher	
> Jim	him	
> Ted	me	
> Dave	me	
> Will	you
> Gary	him
> 
> Table:3
> Author	Title	Country
> Ted	B	UK
> Ted	D	US
> Jim	A	UK
> Dave	C	UK
> 
> Combined table: Result
> Author	Title	Publication Date	Publisher	Sales	Country
> Ted	B	J	me	bb	UK
> Ted	D	L	me	dd	US
> Jim	A	I	him	aa	UK
> Dave	C	K	me	cc	UK
> Gary	null	null	him	null	null	
> Will	null	null	you	null	null
> 
> 
> 
> 
> --
> Sent from: https://www.postgresql-archive.org/PostgreSQL-pgadmin-support-f2191615.html
> 
>