php mysql results backslashes removed

I have a table with file names and some other information in it. When I run the following query:

select * from `documentinfo` WHERE `num`='40217'

I get the results correctly:

Array
(
    [num] => 40217
    [datetime] => 2011-09-15 15:22:07
    [date] => 2011-09-15
    [filename] => C:\redoak\DocumentsIN\Filer\8883894460_3044564210_07334802020001.mp3
)

When I run the query:

QUERY:`filename` REGEXP '^C:\\redoak\\DocumentsIN\\Filer'

I get:

Array
(
    [num] => 35910
    [datetime] => 2010-12-03 17:34:38
    [date] => 2010-12-03
    [filename] => c:
edoakDocumentsINFiler8883894460_3043926485_05863748580001.mp3
)

Notice that the results have the \ removed from the folder name.

I used the following php with both to display this:

while ($row = array_change_key_case(mysql_fetch_assoc($webquery), CASE_LOWER)) 
{
    print_r($row);  
}

Query for any num works just fine. The regexp query works if the pattern does not contain a backslash. If it contains a backslash it works but the data returned from the table is missing it's back slashes. Even though the query finds the correct records. Thank Oak

Is the the problem: The character_set_results Does a regexp query return a different character set results by default then a = query?

I tried the following to change the character set to see what happened:

mysql_query("SET character_set_results = 'utf8', character_set_client = 'utf8', character_set_connection = 'utf8', character_set_database = 'utf8', character_set_server = 'utf8'") or die("ERROR SETTING CHAR SET");      
echo '<pre>debug: encoding=', mysql_client_encoding(), '</pre>';

$webquery=mysql_query($query);

echo '<pre>debug: encoding=', mysql_client_encoding(), '</pre>';

it always indicates latin1

I used mysql_set_charset('utf8'); and it changed to utf8 but the results did not change.

MySQL interprets a backslash character as an escape character. For backslash in a query use double backslash \\