website development: sql query returning only case-sensitive values when using LIKE to query from the database

Question

 <?php 
$searchErr="";

function test_input($data) {
            $data = trim($data); //whitespacess
            $data = stripslashes($data); //removes backslashes n clean data from database or form
            $data = htmlspecialchars($data); //converts predefined characters to html entities, encoding user input so that they cannot manipulate html codes
            return $data;
            }

if ($_SERVER["REQUEST_METHOD"]=="POST")
{

    if(isset($_POST["searchQuery"]))
    {
        if(empty($_POST["searchQuery"]))
        {
            $searchErr="Field cannot be empty!";
        }

        else //no error
        {




            $searchData=test_input($_POST["searchQuery"]);
            $searchData=preg_replace("#[^0-9a-z]#i","",$searchData);

            echo $searchData;
            require_once('includes/db_connect.php');


            $sQuery ="SELECT * FROM food WHERE Food_Name LIKE BINARY :searchData OR Food_Description LIKE BINARY :searchData";


            $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

            $stmt=$conn->prepare($sQuery);

            $stmt->bindParam(':searchData',$searchData); //binding var to parameter
            $stmt->execute(); //executing prepared statement and returning 

result to obj $numResults=$stmt->rowCount();

            if($numResults==0)
            {
                $msg="Your search did not match any of our available 
       foods!";
                echo $msg;
            } 

            else
            {
                while($row=$addResult->fetch(PDO::FETCH_ASSOC))
                {
                    echo $row['Food_Name'];
                    echo "<br/>";

                }
            }

        }

    }

   }



        ?>

        <?php

I am currently working on a website. In a section, I have a search bar which i use to search for text- match from my database. However, when I am getting the results, only texts which are case-sensitive are being returned. Please can u help me? I am using Apache and phpMyAdmin

Answer 1

MySQL LIKE operator is case insensitive by design, unless the related column has a case-sensitive collation.

If you want a case-sensitive seach, you can use LIKE BINARY .

SELECT * 
FROM food 
WHERE 
    Food_Name LIKE BINARY :searchData 
    OR Food_Description LIKE BINARY :searchData

On the other hand, if your column has a case-sensitive collation and you want a case insensitive search, you can use lower() to turn both the column values and the search term to lower case before comparing:

SELECT * 
FROM food 
WHERE 
    LOWER(Food_Name) LIKE LOWER(:searchData)
    OR LOWER(Food_Description) LIKE LOWER(:searchData)

Please note that both approaches are not index-friendly. Bottom line, you want to use a column collation that does match your need. If you want a case-insensitive match, use a case-insensitive collation, else use a case-sensitive collation.

Important side note: your code is vulnerable to SQL injection. Do read about bind parameters and prepared statement , and consider fixing your code. I updated your query so it uses named bind variables.