我如何在MySQL PHP中使用OR语句

Question

I am trying to make a live search box for a library using ajax, mysql and php. I have implemented the search for the books. ie when you type in the title of the book, it shows the suggestions. However, I am trying to implement it also for the authors column in my database such that when you type in a name of an author, it shows the books that the author has written from the database but I don't seem to be getting the mysql statement on line 4 correctly. please help.

<?php
include('config.php');
$s1=$_REQUEST["n"];
$sql="SELECT * from books where (Title like '%".$s1."%') OR (Author like '%'.s1.'%')";
$result=mysqli_query($conn,$sql);
$s="";

Answer 1

<?php
include('config.php');
$s1=$_REQUEST["n"];
$sql="SELECT * from books where `Title` like '%".$s1."%' OR `Author` like '%".$s1."%')";
$result=mysqli_query($conn,$sql);

Answer 2

You have some misplaced quotes as well as missing $ in your query code line. So You need to change

Author like '%'.s1.'%'

To:-

Author like '%".$s1."%'

Note:- Your Query is wide-open for SQL INJECTION .So try to use prepared statements

Reference:-

mysqli::prepare

PDO::prepare

Answer 3

Personally I dont like OR's. Instead I prefer Union. Hey I get paid by the hour (actually I get salary) But I still like to over complicate things.

<?php
include('config.php');
$s1=$_REQUEST["n"];
$sql="
    SELECT
         b.*
    FROM
        books AS b
    JOIN
        (
            SELECT
                id
            FROM
                books
            WHERE 
                Title like ?'
        UNION
            SELECT
                id
            FROM
                books
            WHERE 
                 Author like ?
        ) AS v
    ON b.id = v.id  
";

$stmt = mysqli_prepare($conn,$sql);

$stmt->bind_param("ss", '%'.$si.'%', '%'.$si.'%');
$stmt->execute();

$stmt->store_result();

$resultrow = array();
$stmt->bind_assoc($stmt, $resultrow);

while($stmt->fetch())
{
    print_r($resultrow);
}

No actually the performance is better, OR's are crap for performance. And if you do it in a sub query with just the ID, then the tempory table you create by doing the union is tiny and then join and pull just what you want, sort etc... And it should be a few times faster, if you have like a couple million records.