Pls help me..Any given idea is welcome.

Question

Am been working on this project.
I created a table called drugs & created another table called orders...
Now i have like quantity as a column in my drugs table..
In orders table how can someone makes an order of a drug so it should subtract it from the qauntity column of the drug table...
E.g

Drugs table.... Has a column named quantity...
We have quantity as 5...
The how can one makes 1 order so it should subtract it from 5 to remainder 4 to be left in quantity...
Pls any observation thanks for listening.

Answer 1

the only way to decrease quantity is to update:

$result = $conn->query("select quantity from drugs where columnname = columnvalue ");

if($row = $result->fetch_assoc()){

$newqty = $row['quantity'] - 1;

$query = "update drugs set quantity = $newqty where columnname = columnvalue ";

if( $conn->query($query)){
echo "updated";
}else{
echo "fail to updated";
}

}

Answer 2

What are you using this in? php or js?

Answer 3

Coder's Crux is php

Answer 4

Well then, you can simply run a query to the table called drugs, using mysqli_query() and then run a query to deduct the quantity of drugs from the current stock.

EDIT: Also, what use is the drugs table? Do you have multiple rows with different types of drugs in them?

Answer 5

Soo Zhan Nam Thank you