MYSQL query: AND OR?

[Bonge Boo!]

This will probably sound stupid.

How would you do a MYSQL query that was to evaluate if either condition A or
B was meet? And if so, in what order would the result come out?

Say I have

select * from images where model_ID ={$_REQUEST['model_ID']} , image_ID =
{$_REQUEST['image_ID']}

I know I could do an XOR, which is "if either, but not both" but I don't
know what "if either, use A first" would be.

[Chris Hope]

Bonge Boo! wrote:

> This will probably sound stupid.
>
> How would you do a MYSQL query that was to evaluate if either condition A
> or B was meet? And if so, in what order would the result come out?
>
> Say I have
>
> select * from images where model_ID ={$_REQUEST['model_ID']} , image_ID =
> {$_REQUEST['image_ID']}
>
> I know I could do an XOR, which is "if either, but not both" but I don't
> know what "if either, use A first" would be.

Do you mean this is what you want?

select * from images where model_ID = 'foo' or image_ID = 'bar'

Unless you specifically set the order using "order by" the order is
essentially random eg you could order it "order by model_ID, image_ID"

--
Chris Hope - The Electric Toolbox - [url]http://www.electrictoolbox.com/[/url]

[Bonge Boo!]

On 7/7/04 9:57 pm, in article 1089233879_15263@216.128.74.129, "Chris Hope"
<blackhole@electrictoolbox.com> wrote:

>> Say I have
>>
>> select * from images where model_ID ={$_REQUEST['model_ID']} , image_ID =
>> {$_REQUEST['image_ID']}
>>
>> I know I could do an XOR, which is "if either, but not both" but I don't
>> know what "if either, use A first" would be.

>
> Do you mean this is what you want?
>
> select * from images where model_ID = 'foo' or image_ID = 'bar'
>
> Unless you specifically set the order using "order by" the order is
> essentially random eg you could order it "order by model_ID, image_ID"

Not really. I was hoping for:

If A is true OR b is true do something, but if b is true, then ignore the a
part and just return b query

I'm not explaining very well. The problem I had is that when my query is
looking for 2 variables to be passed, if one of them isn't there, then the
query fails with an error message.

I was trying to have a page which says "if no value for image_ID" is set,
then simply use the model_ID to get a result out, which will display an
image.

However if an explicit image_ID is set, then return this image.

Maybe I'm doing this wrongly and should be using

if (isset($image_ID) {

Do this mysql query
}else {

Do another mysql query
}

Problem is I'm using Golive and its never that keen on you messing with the
"content sources" Dreamweaver also behaves similarly AFAIK.

[Alvaro G Vicario]

*** Bonge Boo! wrote/escribió (Thu, 08 Jul 2004 09:04:44 +0100):

> If A is true OR b is true do something, but if b is true, then ignore the a
> part and just return b query

You really want two separates queries, don't you?

select this from table where a or b
select that from table where not b

> I'm not explaining very well. The problem I had is that when my query is
> looking for 2 variables to be passed, if one of them isn't there, then the
> query fails with an error message.

Then use PHP to compose a custom query string.


--
--
-- Álvaro G. Vicario - Burgos, Spain
--

[bill]

On Wed, 07 Jul 2004 20:50:20 +0100, Bonge Boo! <bingbong@spamcop.net>
wrote:

>How would you do a MYSQL query that was to evaluate if either condition A or
>B was meet? And if so, in what order would the result come out?

A ternary operator might be what you're looking for:

($a = true) ? ($do = "a and b") : ($do = "");

[url]http://us2.php.net/language.operators[/url]

[George Hernandez]

SELECT * FROM your_table_name WHERE condition_1 AND condition_2

"bill" <whoami@whereami.not> wrote in message
news:ikhte0hqdrfrsmino3hh8erhpihjqu3sgt@4ax.com...
: On Wed, 07 Jul 2004 20:50:20 +0100, Bonge Boo! <bingbong@spamcop.net>
: wrote:
:
: >How would you do a MYSQL query that was to evaluate if either condition A
or
: >B was meet? And if so, in what order would the result come out?
:
: A ternary operator might be what you're looking for:
:
: ($a = true) ? ($do = "a and b") : ($do = "");
:
: [url]http://us2.php.net/language.operators[/url]
:
: