我们可以在php类的单个方法中使用两个mysql查询吗？

Question

I am wondering that whether it is possible to write two different mysql queries in one php class object method and use those results in an another class method. Here's I am trying to do (I put only the relevant part of my code here), but I think it's not working:

<?php

    public function sql()
    {
        $sql = "SELECT * FROM customers";

        // Another sql
        $sql_sales = "SELECT SUM(sales) as sales FROM customers";
        // Execute this sql and result is stored in a variable
        $this->sales = $row['sales'];

        return $sql;
    }

    public function customers_list()
    {
        $sql = $this->sql();

        $customers = '
        <div id="customers">
            <div id="customers_num"><span>'.$this->sales.'</span> Sales</div>
        </div>';
        return $customers;
    }

?>

Can we use value of variable $this->sales inside another method?

If not then what's the correct way of getting it's value?

Answer 1

In case your code is inside a class and you're using an instantiated object :

From PHP basics

The pseudo-variable $this is available when a method is called from within an object context. $this is a reference to the calling object

Therefore you can access any of your object properties inside its methods.

In your specific case $this->sales = $row['sales']; stores a value in its sales property which can be used anywhere else in the object scope.