Question

I can’t deal with it. I’m experiencing big troubles with this very query:

UPDATE books 
SET books.out = books.out + 1 
WHERE id = 81813130; 

UPDATE books 
SET books.available = 0 
WHERE books.in = books.out;

If I run it on my phpMyAdmin, everything’s fine and everything completes, but in my CakePHP application this query doesn’t work and when I perform a debug this is what I’m told:

Warning (512): SQL Error: 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 ‘UPDATE books SET books.available = 0 WHERE books.in = books.out’ at line 1**

I’m calling my query from a controller:

$this->Lending->update_lendings($this->data['Lending']['book_id']);

and the actual query is of course into the model:

$query = "
    UPDATE books 
    SET books.out = books.out + 1 
    WHERE id = ".$id."; 

    UPDATE books 
    SET books.available = 0 
    WHERE books.in = books.out;
          ";

I really can’t say why this isn’t working. It seems that error 1064 Mysql is a very common question in here but I didn’t find anything useful about my very issue.

I steadfastly thank you for your support and help.

Answer 1

If the second Update statement is meant to change only the row that the first statement updated, then you could use a single Update:

UPDATE books 
SET out = out + 1
  , available = CASE WHEN in = out
                       THEN 0
                       ELSE available
                END
WHERE id = 81813130