On 7/12/07, mos <[EMAIL PROTECTED]> wrote:
BTW, joins will work faster if you load one or more tables in a Memory
table before you do the join.
Well, if your tables are so small that you can load them entirely into
memory, it probably doesn't matter how you code the query.
- Perrin
--
MySQL G
At 07:26 PM 7/12/2007, Perrin Harkins wrote:
On 7/12/07, Jerry Schwartz <[EMAIL PROTECTED]> wrote:
Since the "rows" is identical except for the last bit, where mine is 4 and
yours is 2, does that mean yours is roughly more efficient by a 2:1 ratio?
For the most part, MySQL will do better with
On 7/12/07, Jerry Schwartz <[EMAIL PROTECTED]> wrote:
Since the "rows" is identical except for the last bit, where mine is 4 and
yours is 2, does that mean yours is roughly more efficient by a 2:1 ratio?
For the most part, MySQL will do better with LEFT JOIN than an IN
subquery. You can read a
On 7/12/07, Jerry Schwartz <[EMAIL PROTECTED]> wrote:
I think that will give me one record for every price that is not Yen, so if
a product has a price in USD and a price in GBP it will show up twice.
That would happen if you removed the 'USD' condition from the first
JOIN. Like I said, I'm no
My apologies, you were correct: I left out a line from my query, so it would
have given bogus results except for the fortunate fact that every product
having at least one price has a USD price.
The EXPLAIN output didn't change.
Regards,
Jerry Schwartz
The Infoshop by Global Information Incorpora
I never thought of putting an additional condition on the LEFT JOIN. That
seems to do the trick.
My original query, with the sub-SELECT, does work. Both your technique and
mine generate identical results.
I did an EXPLAIN on each technique, but I don't know enough to interpret it.
Since the "row
2007 12:05 PM
To: Jerry Schwartz
Cc: mysql@lists.mysql.com
Subject: Re: SELECT missing records
Try this
SELECT prod.prod_num, price.prod_price
FROM prod JOIN price
WHERE prod.prod_id = price.prod_id
AND price.prod_curr !='YEN';
On 7/12/07, Jerry Schwartz <[EMAIL PROTECTED]&
On 7/12/07, Jerry Schwartz <[EMAIL PROTECTED]> wrote:
I believe this query
will do it, but can it be redone without the sub-query by using JOINs?
Yes, use a LEFT JOIN.
Would that be more efficient?
Yes.
SELECT prod.prod_num, price.prod_price
FROM prod JOIN price
WHERE prod.prod_id = price
Try this
SELECT prod.prod_num, price.prod_price
FROM prod JOIN price
WHERE prod.prod_id = price.prod_id
AND price.prod_curr !='YEN';
On 7/12/07, Jerry Schwartz <[EMAIL PROTECTED]> wrote:
I've been banging my head against the walls for hours, so I hope somebody
can help. I know similar questi
I've been banging my head against the walls for hours, so I hope somebody
can help. I know similar questions have been answered in the past.
I have two tables, prod and price. Stripping out the non-essential fields,
they are pretty simple:
prod
---
prod_num (int)
prod_id (char 15)
price
Dave,
Saturday, August 24, 2002, 2:53:59 AM, you wrote:
DR> I upgraded my server and seem to have lost some MySql records. Is there a way to
recover lost records?
DR> Or could it be a index problem?
If you check tables with CHECK TABLE clause, do you get any error or
warning? If so, repair tabl
Pada Fri, 23 Aug 2002 16:53:59 -0700
Dave Reinhardt <[EMAIL PROTECTED]> menulis :
> I upgraded my server and seem to have lost some MySql records. Is there a way to
>recover lost records?
> Or could it be a index problem?
how did you upgrade it ? and from what information you notice that you've
12 matches
Mail list logo
