sql error:

query:
SELECT concat(FirstName,' ',LastName) FROM tblArtists WHERE ArtistID=

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1.
if you haven't set up
< backArray ( [CONTEXT_DOCUMENT_ROOT] => /home/cathyd/public_html [CONTEXT_PREFIX] => [DOCUMENT_ROOT] => /home/cathyd/public_html [GATEWAY_INTERFACE] => CGI/1.1 [HTTP_ACCEPT] => text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 [HTTP_ACCEPT_ENCODING] => x-gzip, gzip, deflate [HTTP_HOST] => gallerydeforest.com [HTTP_USER_AGENT] => CCBot/2.0 (http://commoncrawl.org/faq/) [PATH] => /bin:/usr/bin [PHPRC] => /usr/local/lib/ [QUERY_STRING] => Artist=1&Cat=146 [REDIRECT_STATUS] => 200 [REMOTE_ADDR] => 54.162.76.55 [REMOTE_PORT] => 60654 [REQUEST_METHOD] => GET [REQUEST_SCHEME] => http [REQUEST_URI] => /artist-thumbs.php?Artist=1&Cat=146 [SCRIPT_FILENAME] => /home/cathyd/public_html/artist-thumbs.php [SCRIPT_NAME] => /artist-thumbs.php [SERVER_ADDR] => 162.144.254.151 [SERVER_ADMIN] => webmaster@cathydeforest.com [SERVER_NAME] => gallerydeforest.com [SERVER_PORT] => 80 [SERVER_PROTOCOL] => HTTP/1.0 [SERVER_SIGNATURE] => [SERVER_SOFTWARE] => Apache [UNIQUE_ID] => WVPOmqKQ-pcAAHzWXMAAAAAD [PHP_SELF] => /artist-thumbs.php [REQUEST_TIME_FLOAT] => 1498664602.06 [REQUEST_TIME] => 1498664602 [argv] => Array ( [0] => Artist=1&Cat=146 ) [argc] => 1 )
POST
Array ( )
GET
Array ( [Artist] => 1 [Cat] => 146 )