query works on MySQL, but no in PHP, why?

I need to display the results of this query :

SELECT * FROM projects WHERE PrestaCmd LIKE '% A -  CREP -  DPE - %'

but in PHP, this query doesn't work :s

This is my code :

$req = "SELECT * FROM ".$table." WHERE PrestaCmd LIKE '%".$ch."%'";

echo $req; //returns : SELECT * FROM jos_projectlog_projects WHERE PrestaCmd LIKE '% A -  CREP -  DPE - %'

$results = mysql_query($req);

while ($row = mysql_fetch_array($results, MYSQL_ASSOC)) {
   print_r($row);
}

I think the problem is coming from the '$ch' variable. But when I put an echo of the quer开发者_开发百科y, it's correct, and when I put a query like this :

$req = "SELECT * FROM jos_projectlog_projects WHERE PrestaCmd LIKE '% A -  CREP -  DPE - %'";

echo $req; 
$results = mysql_query($req);

while ($row = mysql_fetch_array($results, MYSQL_ASSOC)) {
   print_r($row);
}

it works :s

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@Bahumat100, if you think you have   to make space which is causing problem, then use html_entity_decode and do it like this:

$req = "SELECT * FROM ".$table." WHERE PrestaCmd LIKE '%".html_entity_decode($ch)."%'";