What's wrong with this query?

I’m not that experienced with MySQL, but I thought I knew enough to do what I need this time. But I’m getting completely unexpected results and can’t figure out the problem.

Here’s the query I’m using:

SELECT channels.name, channels.description, categories.name, categories.description FROM channels, categories WHERE channels.title='$var' OR categories.title='$var'

$var contains a string that will be the ‘title’ of either a channel or a category. The query is intended to check both tables and return the applicable row from whichever table it finds a match for $var in the ‘title’ field. There are no duplicate ‘title’ field values between the two tables.

The actual results I’m getting are a full list of all rows in whichever table it shouldn’t have found a match in at all. In other words, when $var should match a single row in the ‘channels’ table, the query actually returns ALL rows in the ‘categories’ table, and vice-versa.

What do I need to modify to get the expected results?

Thanks for any ideas,


you forgot to join the matching rows

change this –

FROM channels, categories 
WHERE channels.title='$var' OR categories.title='$var'

to this –

  FROM channels
  JOIN categories 
    ON [COLOR="#0000FF"]categories.id [/COLOR]= [COLOR="#0000FF"][/COLOR][COLOR="#0000FF"]channels.category_id[/COLOR]
 WHERE channels.title = '$var' 
    OR categories.title = '$var'

see those two columns marked in blue? i guessed at the names

Thank you for such a quick reply. Unfortunately, I’m not sure JOIN is what I’m after because the two tables in question have no relationship, and really, no relevance to one another. I just need to know which table $var is found in.

I did try the code you suggested, but it also yielded strange results by fetching data from both tables from rows where the ID’s matched one another. I only want to retrieve data from one row from whichever table matches $var - the other fields I’m using for SELECT can remain null as they won’t be used anyway.

Is there any way to accomplish this?

  , channels.description
FROM channels
WHERE channels.title='$var'
  , categories.name
  , categories.description 
FROM categories 
WHERE categories.title='$var'