使用子字符串搜索字段的值

I'm working on a project using the pages in php / mysql and html; I have a table that contains the data for calls made from a PBX and save the number called, the source, date, time, etc ... what I want to do is to search within this table all the phone numbers that have the first 4 digits equal to those that pass through the query, only that i have no idea how to pull off only the 4-digit or at least how to make a control character by character of the value contained in the field. I tell you now that the field is a varchar. Thank you in advance :)

To do that in MySQL query, either

SELECT *
FROM <tablename>
WHERE LEFT(<column>, 4) = "<4 digits>"

or

SELECT *
FROM <tablename>
WHERE <column> LIKE "<4 digits>%"

or in the PHP side :

if (strpos($column,'<4 digit>') !== false) {
    echo 'true';
}

Use this, to get substring

SELECT aut_name,  
RIGHT(aut_name,7)   
FROM author   
WHERE country='UK'; 

I suggest this solution: $variableWhereYoustoreTheFourDigits="1234"; //Use whatever you have in your code to set the value.

$result =$mysqli->query("SELECT number FROM yourtable where number LIKE \"$variableWhereYoustoreTheFourDigits%\");