Why I am getting the Error “Commands out of sync;

问题:

The Documentation of the Error Mentioned in the Title Says

If you get Commands out of sync; you can't run this command now in your client code, you are calling client functions in the wrong order.

This can happen, for example, if you are using mysql_use_result() and try to execute a new query before you have called mysql_free_result(). It can also happen if you try to execute two queries that return data without calling mysql_use_result() or mysql_store_result() in between.

From here: http://dev.mysql.com/doc/refman/5.0/en/commands-out-of-sync.html

But In First Query I am not fetching any data from mysql database, I am just inserting. And In second Query I am getting the data from database.

Here is My code

$connection = mysqli_connect("localhost","username","password","tbl_msgs");
if(mysqli_connect_errno($connection))
{
    die("Failed to connect to MySQL: " . mysqli_connect_error());
}
$query = "INSERT INTO users (total_comments, total_views) 
          VALUES ({$total_comments}, {$total_views});";

$query .= "INSERT INTO msgs (notifications) VALUES ({$notifications})";

mysqli_multi_query($connection,$query);

Upto this Step every thing is fine. But When I execute the following query It gives the Error

$select_query = "SELECT * FROM msgs WHERE msg_id = {$msg_id}";

$result_set = mysqli_query($connection,$select_query);

if(!$result_set) {
    die(mysqli_error($connection)); 
}

Here it gives the Error Commands out of sync; you can't run this command now. I can't understand this situation

Note: There is any Problem in the Query, I have executed the same query directly to PHPMyAdmin and it works fine.

回答1:

There are result set pending from the query:

mysqli_multi_query($connection,$query);

You need to use/store result before you can proceed with next query after: Since you look like you don't really care about the first result set, do this after the multi query..

do
{
    $result = mysqli_store_result($connection);
    mysqli_free_result($result);
}while(mysqli_next_result());

Another alternative is to close the connection and starts it again..

mysqli_close($connection);
$connection = mysqli_connect("localhost","username","password","tbl_msgs");

It all depends on your requirements.