I can't comment on whatever Borland client you're talking about but MySQL
supports multiple table joins. It's all in your sql coding. I built a
yellow pages directory using MySQL that consists of several tables. One has
500,000 records another has 2,000,000 records, others are smaller having
between 3 and 1000 records. Most calls involve joining both the two large
tables and three or four of the smaller tables.
Fred Steinkopf
----- Original Message -----
From: "Erlend Stromsvik" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, August 06, 2001 7:45 AM
Subject: Re: Borland MySQL client
> Hi
>
> I having a little trouble with mysql, with the lack of sub-selects.
>
> Yes, I have read about joins, both the manual and from the MySQL book by
> Paul Dubois, but none of those provide any 'real' info about what to do.
>
> It's ok to do join on table1, table2 and table3 as long as they are
limited
> to 10 records each, as in all of the examples you find on the net. But
what
> about my tables. I have one with 1,14 million and one with 136.000 and a
> third with 65.000 records. What I want to do is to check for a match
between
> a record from table1 in table2 and from table1 to table3
>
> ex. from table1 to 2:
> select * from table1 where col1 in (select col2 from table2);
>
> If I where to do a join on those tables I would, to my knowledge, end up
> with a temp table with 1,14 * 136.000 * 65.000 records.. And that's a HUGE
> table. I'm actually not even going to try it, because I'm pretty sure it
> won't work.
>
> The only solution I seem to find, is to include two new columns in table1,
> where you give them either TRUE or FALSE based on the info put into table2
> and table3.
>
> So whenever I do an insert in table2 or 3, I also update corresponding
> record in Table1 with TRUE in either one of the two columns. <- Would
this
> be the 'right' way to do it? :)
> This way I only have to retrieve the record from table1, check for TRUE
> value in the two columns, if they are TRUE retrieve record from table2 and
> from table3.
>
> Would be nice to hear from someone who manages good sized databases.
>
>
> Regards
> Erlend Stromsvik
>
>
>
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