array to string convertion error in php

Question

I am using the following code for passing the array value into mysql query but array to string conversion error will come

$sql =mysql_query("SELECT userId from groupmembers where groupId='$groupId'");
$bjson = array();
$i = 0; 
while($result=mysql_fetch_assoc($sql))
{ 
    $bjson[$i]['userId'] = $result['userId'];

    $i++; 
}

$query = "SELECT firstName 
     FROM users 
     WHERE userId IN('" . implode("','", $bjson) ."')";

Please stop using mysql_* functions. These extensions have been removed in PHP 7. Learn about prepared statements for PDO and MySQLi and consider using PDO, it's really pretty easy. — Jay Blanchard
– Jay Blanchard, Commented Mar 28, 2016 at 12:24

Community · Accepted Answer · 2017-05-23 11:50:40Z

6

No need of two query and loop just use

SELECT firstName 
     FROM users 
     WHERE userId IN(SELECT userId from groupmembers where groupId='$groupId')

Note:- mysql is deprecated instead use mysqli or PDO

Read How can I prevent SQL injection in PHP?

edited May 23, 2017 at 11:50

CommunityBot

11 silver badge

answered Mar 28, 2016 at 12:25

Saty

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Comments

user2762134 · Accepted Answer · 2016-03-28 12:26:34Z

1

Can use a join in your query to save the loop

SELECT u.firstName FROM users u JOIN groupmembers gm ON gm.userID = u.userID WHERE gm.groupID='$groupId'

answered Mar 28, 2016 at 12:26

user2762134

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