Looping the WHERE section of mysql query - php

Question

I'm trying to determine whether a combination of topics related to a category is unique. This is done while adding topics to a category. The uniqueness is checked with this query:
$sql_unique = "SELECT Categories_CategoryID, list
FROM (
SELECT Categories_CategoryID, GROUP_CONCAT( Topics_TopicID ) AS list
FROM (
SELECT *
FROM Topics_crosstable
ORDER BY Topics_TopicID
)H
GROUP BY Categories_CategoryID
)A
WHERE list = (
SELECT GROUP_concat( TopicID )
FROM Topics
WHERE Name = 'nr1'
OR Name = 'nr2'
ORDER BY Categories_CategoryID ASC )";
$result = mysql_query($sql_unique);
echo mysql_num_rows($result);
if($result > 1)
{
echo' HELP! It is not unique';
}
else
{
echo ' getshere';
}
This works fine. The problem is however, the number of topics that are added is variant. So is there some way to include a for loop in the where section of the query?
Something like for(number of topics added; nr++) {OR Name =', $inserted_topicName '}

Answer 1

Make use of 'WHERE ... IN':
WHERE Name IN ('nr1','nr2',...)
And
string implode ( string $glue , array $pieces );
Use as follows:
$options = array(); //here's your choices
$sql_unique = "SELECT Categories_CategoryID, list
FROM (
SELECT Categories_CategoryID, GROUP_CONCAT( Topics_TopicID ) AS list
FROM (
SELECT *
FROM Topics_crosstable
ORDER BY Topics_TopicID
)H
GROUP BY Categories_CategoryID
)A
WHERE list = (
SELECT GROUP_concat( TopicID )
FROM Topics
WHERE Name IN (";
$sql_unique .= implode(",",$options);
$sql_unique .= ") ORDER BY Categories_CategoryID ASC )";

Answer 2

table Categories
catID
table Topics
topID
category
Categories : Topics ( 1 : n )
Question: does category $x have unique set of topics?
first get sum of all topics of category $x
SELECT GROUP_CONCAT(topID ORDER BY topID) topiclist
FROM Topics
WHERE category='$x'
you may need to explode the topiclist and add some new values to that array, I am assuming that the result of the above query was fetched into an associative array $r
$list=explode(',',$r['topiclist']);
$list[]=$newtopicID1;
$list[]=$newtopicID2;
// etc ... or use $list += $newTopicsArray; which will ADD those two arrays
sort($list); //make it sorted again
$list=implode(',',$list);
and then query the database again, trying to find such a combination excluding the category i am querying:
SELECT GROUP_CONCAT(topID ORDER BY topID) topiclist
FROM Topics
WHERE category!='$x'
GROUP BY category
HAVING topiclist='$list'
then check whether there is some record returned. If so, then you found another category with the same topics, if not, then the combination of topics is unique