Adding two variables containing integer values - sql

Question

I have fetched integer data in two variables from different tables. I need to apply the add operation so that I can get the sum of the values in those variables. I am a beginner though so please try to help me out here. I tried the code in Model and the result I am getting is : Object of class CI_DB_mysqli_result could not be converted to int
$fromrequest = $this->db->query("SELECT Requests.sunit FROM Requests WHERE Requests.sid = 2");
$fromstock = $this->db->query("SELECT Stock.sunit FROM
Stock WHERE Stock.ssid = 5");
$sum = $fromrequest + $fromstock

Answer 1

first your queries are not definite. Look at "SELECT Requests.sunit FROM Requests", the query is going to list all Sunits in the table Requests. But you want to count or sum the sunit and assign them to the valuable $fromrequest the query like
$fromrequest = $this->db->query("SELECT count(Requests.sunit) as Units FROM Requests");
or
$fromrequest = $this->db->query("SELECT sum(Requests.sunit) as Units FROM Requests");
would results into an integer which would make your life easy. Try it and we see what we get. Good luck

Answer 2

check the values and better use active record..
$get_fromrequest = $this->db->select('sunit')->where('sid',2)->get("Requests");
$fromrequest = $get_fromrequest->row();
if(isset($fromrequest)){
$freq = $fromrequest->sunit;
} else {
$freq = 0;
}
$get_fromstock = $this->db->select('sunit')->where('ssid',2)->get("Stock");
$fromstock = $get_fromstock->row();
if(isset($fromstock)){
$fstock = $fromstock->sunit;
} else {
$fstock = 0;
}
chang it
$sum = $fromrequest + $fromstock
to
$sum = abs($fromrequest) + abs($fromstock);