PHP exception: SQLSTATE[42000]: Syntax error or access violation: 1064 - php

Question

I have a php pdo script where I want to select the record (from a table in a MySQL database) with the highest number in "field5". I also have a few other constrictions, see below:
$stmt=$db->query("SELECT `field1`,`field2` FROM ".$tablename." WHERE
`field3`!=".$variable1." AND `field3`!=".$variable2." AND
`field4`='xx' AND `field5`<".$variable3." ORDER BY DESC `field5` LIMIT
1");
I have pretty much all the code inside a try-statement, and in the catch statement I use
var_dump($ex->getMessage());
to get the exception message from the exception $ex.
Now, when I execute the code I get the following exception message:
'SQLSTATE[42000]: Syntax error or access violation: 1064 You have an
error in your SQL syntax; check the manual that corresponds to your
MySQL server version for the right syntax to use near 'DESC field5
LIMIT 1' at line 3' (length=232)
I'd be grateful for any advice on what might be wrong!

Answer 1

Change
ORDER BY DESC field5
into
ORDER BY field5 DESC

Answer 2

Kindly refer the MySQL manual for the syntax of select query. You have made a simple mistake which is, the query was syntactically wrong. You can only order the column by referencing it initially :
ORDER BY '{Column-Name}'
and then only you can define how it can be ordered either in ASC or DESC.
ORDER BY '{Column-Name}' [ASC|DESC]
So you have to change the query as shown here :
$stmt=$db->query("SELECT `field1`,`field2` FROM ".$tablename." WHERE
`field3`!=".$variable1." AND `field3`!=".$variable2." AND
`field4`='xx' AND `field5`<".$variable3." ORDER BY `field5` DESC
LIMIT 1");