将查询返回的数据库列值排序为数值

Question

Issue : I am writing a query that involves a count() operation on a column but returns the count in the string format. As a result the sorting on the front end is messed up.

Details: I am writing the following query in Zend:

$select = $this->select()
        ->setIntegrityCheck(false)
        ->from(array('s' => 'student'),
            array('s.id', 
            'start_date' => new Zend_Db_Expr("date(s.start_date)"), 
            ))
        ->joinLeft(array('ps' => 'pstudent'), 
                's.id = ps.st_id',
                array('pscount' => new Zend_Db_Expr('count(ps.st_id)')  ))
        ->where('ps.status = "phd"');

$result = $this->getAdapter()->fetchAll($select);

This query returns me the pscount by using the Zend_Db_Expr (count(ps.st_id)) . At a later point in code I encode this data to json format and return to the front end. Since the data from db comes as a string (ie pscount is a string), when I sort on the front end on pscount column of the grid, I get the following sequence.

1
10
100
11
12
13

However,I want it to sort by numeric value so the output is:

1
10
11
12
13
100

I tried writing the Zend_Db_Expr as new Zend_Db_Expr('cast(count(ps.study_id) as signed)') but there is no change in the results. I cannot use an order by in the query as well due to application requirements. The only other option is if I traverse through the $result and then do a (int) type conversion in php code. However that is the last option. I would prefer to do this in mysql query so that I do not have to traverse through the results unnecessarily.

Any help is really appreciated.

Answer 1

Just get it as an array of strings and use sort($someArray, SORT_NUMERIC) . This will sort them as if they were numbers.

If you need to sort complex objects, use usort() with a comparison function.

I don't believe you can order results inside mysql without using order by .