Calculate Max # Query not Failing?!

[doubledee]

This is going to sound weird, but I am trying to break my latest query to make sure my error-handling code is working.

 

Turns out it is NOT working?!

 

Here is my code...

 

// **********************
// Find Last CommentNo.	*
//***********************

// Build query.
$q2 = "SELECT MAX(comment_no) AS lastCommentNo
		FROM comment
		WHERE article_id=?";

// Prepare statement.
$stmt2 = mysqli_prepare($dbc, $q2);

// Bind variable to query.
mysqli_stmt_bind_param($stmt2, 'i', $articleID2);

// Execute query.
mysqli_stmt_execute($stmt2);

// Store results.
mysqli_stmt_store_result($stmt2);

// Check # of Records Returned.
if (mysqli_stmt_num_rows($stmt2)==1){
	// Maximum Found.

	// Bind result-set to variables.
	mysqli_stmt_bind_result($stmt2, $lastCommentNo);

	// Fetch record.
	mysqli_stmt_fetch($stmt2);

	// Increment CommentNo.
	$commentNo = $lastCommentNo + 1;

}else{
	// Maximum Not Found.
	$_SESSION['resultsCode'] = 'COMMENT_MAXIMUM_NOT_FOUND_2049';

	// Set Error Source.
	$_SESSION['errorPage'] = $_SERVER['SCRIPT_NAME'];

	// Redirect to Display Outcome.
	header("Location: " . BASE_URL . "/account/results.php");

	// End script.
	exit();

}//End of FIND LAST COMMENT-NO

 

 

The way I usually test my error-handling is to change a variable name in the Bind statement like this...

 

// Bind variable to query.

mysqli_stmt_bind_param($stmt2, 'i', $articleID2);

 

Here I added a "2" onto $articleID which should make my query fail, but in this case it doesn't?!

 

I am thinking this has something to do with my use of MAX() ?!

 

Right now the query runs but returns "1" for the CommentNo when I was expecting "10" as the next Comment Number...

 

 

 

Debbie

 

 

[doubledee]

If I change my query to this...

 

// Build query.
$q2 = "SELECT comment_no AS lastCommentNo
		FROM comment
		WHERE article_id=?";

// Prepare statement.
$stmt2 = mysqli_prepare($dbc, $q2);

// Bind variable to query.
mysqli_stmt_bind_param($stmt2, 'i', $articleID);

// Execute query.
mysqli_stmt_execute($stmt2);

// Store results.
mysqli_stmt_store_result($stmt2);

// Check # of Records Returned.
if (mysqli_stmt_num_rows($stmt2)==1){
	// Maximum Found.

	// Bind result-set to variables.
	mysqli_stmt_bind_result($stmt2, $lastCommentNo);

	// Fetch record.
	mysqli_stmt_fetch($stmt2);

	// Increment CommentNo.
	$commentNo = $lastCommentNo + 1;

}else{
	// Maximum Not Found.
	$_SESSION['resultsCode'] = 'COMMENT_MAXIMUM_NOT_FOUND_2049';

 

 

...then the query "fails" because several values are returned and my Error Message fires.

 

 

So my question is, if I change $articleID to $articleID2 in my original query, then that means there would be no valid Article ID (i.e. $articleID2 would equal "0") and so my query would return NULL.

 

I guess that is where the problem is occurring.

 

My query is "returning 1 row" which is NULL, but that isn't what I want.

 

Follow me?

 

 

Debbie

 

[trq]

SELECT MAX(blah) FROM tbl WHERE flb = 'whatever'

 

Will always return 1 record.