Mysqli - using select case but other data is not bound

kenno69 · 06-16-2012, 08:08 PM

I'm using Mysqli OO to search the database for 2 specific values using the MySQL statement CASE. If both values are found then it will return the value 'true', if only one is found the value is 'false', if neither are found then the result is neither. Anyway I've got this working but my problem is I need it to also display the values that are related in the column.

PHP Code:


			
$query = "SELECT 'userName','email','code',
CASE 
    WHEN (email=? AND code=?) THEN 'true'
    WHEN (email=?) THEN 'false'
END AS answer
FROM users WHERE email=?";
$stmt = $mysqli->prepare($query);
$stmt->bind_param("ssss", $email,$code, $email,$email);
$email = $mysqli->real_escape_string($email);
$code = $mysqli->real_escape_string($code);
$stmt->execute();
$stmt->bind_result($user,$email,$code,$answer);
$stmt->fetch();
print_r($stmt->fetch);
$stmt->store_result();
echo "User: ".$user." Email: ".$email." Code: ".$code." Answer: ".$answer;

Okay so when I run the code it should display as:

Code:

User: ryan Email: local@localhost Code: 12 Answer: true

But instead it displays it as:

Code:

User: userName Email: email Code: code Answer: true

So I think the error is more to do with the SQL side of it but not sure, I'm stuck and would like some help. Thanks

BTW I have posted it in the PHP area as well just for the simple reason I'm not entirely sure which part it is, so sorry if I'm not allowed to do this

Old Pedant · 06-16-2012, 09:08 PM

Has nothing to do with bind or mysqli.

When you use apostrophes around anything in SQL (any SQL, not just MySQL), you are creating a STRING. A literal string. Exactly what is in the apostrophes.

In other words, if you use

Code:

    SELECT 'username';

You *WILL* get a result of exactly username.

You surely need to and meant to use backticks (the ` character that shares a keyboard key with the ~ tilde).

Code:

$query = "SELECT `userName`,`email`,`code`, ...

But, really, there is no reason to even use them here. You would get the same (correct) results using

Code:

$query = "SELECT userName,email,code, ...

You only need to use the backticks when you use a MySQL keyword as a field name or when your field name contains characters (such as spaces, minus signs, periods) that aren't normally valid in field (and table) names.

Old Pedant · 06-17-2012, 12:59 AM

You have another problem in the SQL, by the by.

Code:

CASE 
    WHEN (email=? AND code=?) THEN 'true'
    WHEN (email=?) THEN 'false'
END AS answer

What happens if email is *NOT* equal to the given value?

You have no WHEN to handle that, so answer will be NULL.

Not sure your CASE really makes sense, as given.