how to query all tables mysql at the same time

1function searchAllDB($search){
2    global $mysqli;
3
4    $out = "";
5
6    $sql = "show tables";
7    $rs = $mysqli->query($sql);
8    if($rs->num_rows > 0){
9        while($r = $rs->fetch_array()){
10            $table = $r[0];
11            $out .= $table.";";
12            $sql_search = "select * from ".$table." where ";
13            $sql_search_fields = Array();
14            $sql2 = "SHOW COLUMNS FROM ".$table;
15            $rs2 = $mysqli->query($sql2);
16            if($rs2->num_rows > 0){
17                while($r2 = $rs2->fetch_array()){
18                    $column = $r2[0];
19                    $sql_search_fields[] = $column." like('%".$search."%')";
20                }
21                $rs2->close();
22            }
23            $sql_search .= implode(" OR ", $sql_search_fields);
24            $rs3 = $mysqli->query($sql_search);
25            $out .= $rs3->num_rows."\n";
26            if($rs3->num_rows > 0){
27                $rs3->close();
28            }
29        }
30        $rs->close();
31    }
32
33    return $out;
34}
35