PHP variable in SQL query which is part of class function is not working as expected

Question

I am trying to pull data from SQL database which match with input year and month. Below is the code for SQL query

 <?php

    class SelectAMonthGet extends ConnectDB {

    var $year;
    var $month ;

        function __construct($n){
            $this->year = $_POST['year'];
            $this->month = $_POST['AnalyzeEnterAreaMonth'];
    }


        function SelectAMonthGetData(){

            $sql = "SELECT * FROM wp_myexpenses WHERE YEAR(date) = '$year' AND MONTH(date) = '$month' order by date,id"; 

            $result = $this->connect()->query($sql);
            $numRows = $result->num_rows;

                if($numRows > 0) {

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

                    $data[] = $row;
                    }

                    return $data;
                }
        }

    }

    ?>

A connectdb function contains my database connection and I am extending that function for this SQL query. But somehow, the code is not recognizing the $_POST variables $year and $month. Above code not giving any result.

I tried to change the SQL query to

$sql = "SELECT * FROM wp_myexpenses WHERE YEAR(date) = '2019' AND MONTH(date) = '1' order by date,id";

and the code works fine. Not sure why the code is not working when I mention the variable. Can someone guide me here?

You should use year and month as $this->year aтd this->month — splash58, Jan 08 '19 at 12:19
Possible duplicate of [Reference: What is variable scope, which variables are accessible from where and what are "undefined variable" errors?](https://stackoverflow.com/questions/16959576/reference-what-is-variable-scope-which-variables-are-accessible-from-where-and) — Nick, Jan 08 '19 at 12:21
See the duplicate. `$year` and `$month` are local to the constructor. You need to declare them as class variables and use `$this->year` as @splash58 said. — Nick, Jan 08 '19 at 12:23
Year $year and $month are local variable. First assign some value to them before executing query. — Umar Abdullah, Jan 08 '19 at 12:36

score 0 · Accepted Answer · answered Jan 08 '19 at 13:17

0

In your code $year and $month are declared as a class variable, and hence you can access them using $this-> (see constructor).

But in your function SelectAMonthGetData in your query, you are using them without this, and hence they were not accessible. To solve this issue, you can use:

$sql = "SELECT * FROM wp_myexpenses WHERE YEAR(date) = '$this->year' AND MONTH(date) = '$this->month' order by date,id";

Or

$year = $this->year; $month = $this->month;
$sql = "SELECT * FROM wp_myexpenses WHERE YEAR(date) = '$year' AND MONTH(date) = '$month' order by date,id";

answered Jan 08 '19 at 13:17

Tejashwi Kalp Taru

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Please share the output of `var_dump($sql);` put this code after the query line – Tejashwi Kalp Taru Jan 08 '19 at 13:26
string(87) "SELECT * FROM wp_myexpenses WHERE YEAR(date) = '' AND MONTH(date) = '' order by date,id" – acr Jan 08 '19 at 13:30
what's your query? Have you updated them as I suggested in my post? Is your POST actually getting values, what's the output of `var_dump($_POST);` put this code in the constructor. – Tejashwi Kalp Taru Jan 08 '19 at 13:30
array(2) { ["action"]=> string(18) "analyzedatasummary" ["analyze_options"]=> string(14) "Select_A_Month" } – acr Jan 08 '19 at 13:37
Looks like I have a problem here – acr Jan 08 '19 at 13:37
Issue was with passing the dropdown value via ajax. Fixed it and its working as expected – acr Jan 08 '19 at 15:11

PHP variable in SQL query which is part of class function is not working as expected

1 Answers1