How to validate if Textfield entered is a mobile number using php and SQL DB

can anyone please help me know how to validate if the field value entered is a phone number using php...
I have used a variable $phone , datatype =varchar 10 in sql db
Now i want to validate that users enter only numbers in that field..

Answer

use preg_match

if(preg_match('/^(NA|[0-9+-]+)$/',$str)) {
        *code here*
} else {
        "code here"
}