Obtaining error message when mysqli->bind_param() fails for graceful error handling

Question

I have the following PHP code:

$inserted = false ;
printf("Record must be inserted.  Old DB ID is %d.\n", $old_db_id) ;
$insertSQL = "INSERT INTO GoogleAuth ("
     .                               "script"
     .                             ", client_id"
     .                             ", client_secret"
     .                             ", refresh_token"
     .                             ", auth_token"
     .                             ", refresh_token_date"
     .                             ", auth_token_date"
     .                             ", client_info_date"
     .                             ", last_used_date"
     .                             ")"
     .            " VALUES(?, ?, ?, ?, ?, ?, ?, ?, NULL) "
                   ;
printf("Preparing statement....\n") ;
$stmt = $mySQL->prepare($insertSQL) ;
if ($stmt) {
    printf("Binding parameters...\n") ;
    if ($stmt->bind_param("sssssiiii"
                        , $page_file
                        , $clientId
                        , $clientSecret
                        , $refreshToken
                        , $authToken
                        , $authTokenDate
                        , $refreshTokenDate
                        , $clientInfoDate
                        , $now
                         )) {
        print("Bind returned true\n") ;
        if ($stmt->execute()) {
            $inserted = true ;
            }
        }
    else {
        printf("Bind failed.  %s\n", $stmt->error) ;
        }
    }
if ($inserted) {
    printf("row inserted.\n") ;
    }
else {
    printf("Insert failed! %s\n", $mySQL->error) ;
    trigger_error("Insert failed.  Dang it!", E_USER_ERROR) ;
    }

When I execute this code, the following is printed:

Record must be inserted.  Old DB ID is 0.
Preparing statement....
Binding parameters...
Bind failed.
Insert failed!

Note that the $stmt->error value and the $mySQL->error values are both empty!

Can you please help me understand how to reliably obtain the error message (and/or error code) associated with these sorts of failures? (I eventually figured out that I was putting 9 variables in place of 8 replacement markers... that's not the point. The point is to figure out how to get the actual errors from mysql.)

Thanks!

EDIT

By the way, I've seen articles like this that talk about interesting reuse of variable names. That does not apply here. $stmt is not used anywhere else in this application.

EDIT2

It was suggested that this is a duplicate of this problem. However, the difference is that the goal here is to obtain the failure message so that it can be analyzed for proper handling. (Some errors may be manageable, depending upon circumstances.) In any event, such process makes it possible to GRACEFULLY close down a program, rather than the rude and immediate result that comes from throwing failure errors. As I read the other problem, the goal is to ensure that an error gets to the log, and the program gets aborted.

Answer 1

The failure (too many types) generates a warning, that's why stmt->error returns nothing, you can retrieve it by calling error_get_last function.

if(!$stmt->bind_param(....))
{
    $err = error_get_last();
    if($err)
        printf("Bind failed.  %s\n", $err['message']) ;
}

Answer 2

Following on the lead of @shingo - after accepting his answer, I have made the following function that I hope may help others along the way in this area.

function GetMySqlError($mysql = null, $stmt = null) {
    // MySQL error reporting is inconsistent.  Sometimes failure error
    // message will be in $mysql->error, sometimes in $stmt->error,
    // and sometimes it's necessary to inspect error_get_last().  Sheesh!

    // This routine will inspect all three, and will return the
    // FIRST nonblank value found in:
    //     stmt->error
    //     mysql->error
    //     error_get_last()['message']

    $messageMySql = "" ;
    $messageStmt  = "" ;
    $err          = null;
    $messageLast  = "" ;
    $returnValue  = null ;

    if (is_object($stmt) && property_exists($stmt, "error")) {
        $messageStmt = $stmt->error ;
        }
    if (is_object($mysql) && property_exists($mysql, "error")) {
        $messageMySql = $mysql->error ;
        }
    if ($err = error_get_last()) {
        $messageLast = $err['message'] ;
        }
    if (strlen($messageStmt) > 0) $returnValue = $messageMySql ;
    elseif (strlen($messageMySql) > 0) $returnValue = $messageStmt ;
    elseif (strlen($messageLast) > 0) $returnValue = $messageLast ;
    return $returnValue ;
    }

This may be called as such:

GetMySqlError($mysql_object) ;
GetMySqlError($myaql_object, $statement_object) ;
GetMySqlError($statement_object) ;

Example:
    printf("MySQL/statement error: %s\n", GetMySqlError($mySql, $stmt)) ;

Thanks again, @shingo

Note: I didn't deem it necessary to include connection errors here. That could be done, but I have my own routines for that already.

Note: This could be made more efficient. I opted for readability for this answer only.