$res = $dbr->select( 'externallinks', [ 'DISTINCT el_from' ],
[ 'el_index' . $dbr->buildLike( $like ) ], __METHOD__ );
$count = $dbr->numRows( $res );
$res = $dbr->select( 'externallinks', [ 'DISTINCT el_from' ],
[ 'el_index' . $dbr->buildLike( $like ) ], __METHOD__ );
$count = $dbr->numRows( $res );