Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, boolean given in

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function car_in_period () {
    $car_id = $_GET['car_id'];
    $date1 = $_GET['date1'];
    $date2 = $_GET['date2'];
    $queryy = "SELECT car_id FROM `form1_weight` WHERE 'car_id' = ".$car_id." AND 'reg_date' BETWEEN '".$date1."' AND '".$date2."'";
    $result4 = select_data ($queryy);
    $num_rows = mysqli_num_rows($result4);

What I have tried:

please help me fix this error i checked my sql table and everything is fine

Posted 4-Jun-21 23:53pm

facebook security

Updated 5-Jun-21 0:55am

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Richard Deeming 7-Jun-21 12:36pm

Your code is vulnerable to SQL Injection[^]. NEVER use string concatenation to build a SQL query. ALWAYS use a parameterized query.
PHP: SQL Injection - Manual[^]

Pretty ironic for an account with "security" in the name. 🤣

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Richard MacCutchan · Answer 1 · 2021-06-05T00:55:00

Solution 1

Please read the documentation: PHP: mysql_query - Manual[^], and you will clearly see that when the query statement fails the call returns the boolean value FALSE. Do not assume that your API calls always do what you think; check the return values first.

Posted 5-Jun-21 0:55am

Richard MacCutchan