Trouble with select query using implode variable in php? - php

Question

I dont know whether it's a duplicate one or not?
Here is what i'm trying:
<?php
session_start();
include('db.php');
$valid_data=$_POST['data'];
if(isset($_POST['data']))
{
$list = isset($_SESSION['strtpnt1']) ? $_SESSION['strtpnt1'] : array();
$_SESSION['strtpnt1'][] =$valid_data;
$a=implode(',',$_SESSION['strtpnt1']);
}
?>
when i use print_r for $_SESSION['strtpnt1'] i could see like this:
array (size=5)
0 => string 'trivandrum' (length=10)
1 => string 'kochi' (length=5)
2 => string 'nagercoil' (length=9)
3 => string 'thrissur' (length=8)
I found nothing wrong with that
when i echoed the imploded variable i find the value like this:
trivandrum,kochi,nagercoil,thrissur
When i tested the imploded data in wampserver phpmyadmin's sql like this i could get an error message:
select start from tbl_place where start NOT IN(trivandrum,kochi,nagercoil,thrissur)
the error message is:
Unknown column 'trivandrum' in 'where clause'
But the query works when string value is passed ie 'trivandrum','kochi' etc.
i dont know what is wrong with my query ...here is the query part
$sql21 = "select start from tbl_place where start NOT IN('".$a."')";

Answer 1

For now you can try this but prepared statement is best for it. You can use PDO or MYSQLi . it doesn't work for you because NOT IN needs the list to individually be quoted and separated by commas.
$a=$_SESSION['strtpnt1'];
$new_a= "'" . implode("','", $a) . "'";
$sql21 = "select start from tbl_place where
start NOT IN($new_a)";
Similar Ideas
:Can I bind an array to an IN() condition?
Proper format for PDO and MySQL IN/NOT IN queries

Answer 2

There is error in your parameter $a value, all values inside IN() should be quoted and separated by commas.
Change your code like following:
$a=implode("','",$_SESSION['strtpnt1']); // ',' => "','"
$sql21 = "select start from tbl_place where start NOT IN('".$a."');";// no change
// NOW the SQL query will became: select start from tbl_place where start NOT IN('trivandrum','kochi','nagercoil','thrissur');
Now it should work.

Answer 3

$sql21 = "select start from tbl_place where start NOT IN('".$a."')";
will querying like this :
$sql21 = "select start from tbl_place where start NOT IN('trivandrum,kochi,nagercoil,thrissur')";
which will treat as a whole string
you have to do in passing variable
$a=implode("','",$_SESSION['strtpnt1']);