How to make a MySQL column value equal a variable in PHP - php

Question

I have in my database a column called counter, i'm trying to save one of the rows of that column into a variable in PHP and make it equal the column rating. I do not want to make it from sql directly, I need to make it through php.
The problem is that when I run the query, the value for rating does not change at all. Please give me a solution
$cntrvalue = "SELECT counter FROM schools WHERE name = 'School1'";
$cntrResult = $this->conn->query($cntrvalue);
$mys1 = "UPDATE schools SET rating = $cntrResult WHERE name = 'School1'";
$this->conn->query($mys1);
Thanks
EDIT:
Sorry the code above gives an error, this is the code that changes nothing
$cntrvalue = "SELECT counter FROM schools WHERE name = 'School1'";
$this->conn->query($cntrvalue);
$mys1 = "UPDATE schools SET rating = $cntrvalue WHERE name = 'School1'";
$this->conn->query($mys1);
EDIT 2:
What i'm trying to do now is that i'm trying to get the value of a SUM query:
$mys4 = "SELECT SUM(`s1`+`s2`*2 +`s3`*3 + `s4`*4 + `s5`*5) FROM schools WHERE name = 'School1'";
$mys4Result = $this->conn->query($mys4);
$mys4Value = $mys4Result->fetch_assoc()[''];
The thing is that there is no column in the db to fetch from for this operation. What am I supposed to do? Thanks

Answer 1

Want you want to achieve, can be done within one mysql query, but if you just want how to fix that code:
You need to use the $cntrResult outside the string. Try string concatenation.
First you need to make sure, you have the correct value, as $cntrResult is not an string object, its an resultset:
$value = $result->fetch_assoc()['counter']
And the query:
"UPDATE schools SET rating = '" . $value . "' WHERE name = 'School1'";