group_concat function not returing all values in mysql--it returns some values with one comma at the end. | Learning Curve- Perfect Tutorial for the beginers

If you execute the below code and try to execute the query through phpmyadmin/php script. it will return only few records not all records.

you can use the below files,db sructure to check the issues

database table- create a table inside the db called ‘test’

CREATE TABLE IF NOT EXISTS `tbl_data` (
`id` int(10) NOT NULL,
  `question_id` int(10) NOT NULL,
  `user_id` int(10) NOT NULL
)

CREATE TABLE IF NOT EXISTS `tbl_data` (

`id` int(10) NOT NULL,

`question_id` int(10) NOT NULL,

`user_id` int(10) NOT NULL

)

# index.php

<?php
include"connect.php";
for($i=0;$i<1500;$i++)
{

$query="insert into tbl_data(question_id,user_id) values('$i','10')";

$result=mysql_query($query,$linkfirst);
}
?>

<?php

include"connect.php";

for($i=0;$i<1500;$i++)

{

$query="insert into tbl_data(question_id,user_id) values('$i','10')";

$result=mysql_query($query,$linkfirst);

}

#connect.php

<?php
$linkfirst = mysql_connect('localhost', 'root', '');
if (!$linkfirst) {
    die('Could not connect: ' . mysql_error());
}
 mysql_select_db('test', $linkfirst) or die('Could not select database.');

?>

<?php

$linkfirst = mysql_connect('localhost', 'root', '');

if (!$linkfirst) {

die('Could not connect: ' . mysql_error());

}

mysql_select_db('test', $linkfirst) or die('Could not select database.');

To get proper values use the below code to set the group_concat_max_len.

SET SESSION group_concat_max_len = 1000000;
select group_concat(question_id) from tbl_data where user_id=’10’

if it is in codeigniter you can use the below code in your model file

$this->db->simple_query(‘SET SESSION group_concat_max_len=1000000’);