Monthly Archives: April 2013

SQL – LEFT OUTER JOIN adding returned null values

In a SQL with LEFT OUTER JOIN I had to sum some columns but some of them returned with NULL value and the result of it was a NULL.

So imagine that we want to add table1`.`columnA`to `table2`.`columnB`, we do something like this

SELECT *, (table1`.`columnA` + `table2`.`columnB`) AS total

and if some of them is NULL the total will be NULL.

What I had to do was this

SELECT *, (ifnull(`table1`.`columnA`,0 ) + ifnull(`table2`.`columnB`, 0)) AS total

And if you want to put it on codeigniter where is how I made it:

$this->db->select('*, (ifnull(`table1`.`columnA`,0 ) + ifnull(`table2`.`columnB`, 0)) AS total', FALSE);

Note the , FALSE, it has to be there.

$this->db->select() accepts an optional second parameter. If you set it to FALSE, CodeIgniter will not try to protect your field or table names with backticks. This is useful if you need a compound select statement.

CodeIgniter – radio and checkbox – value=”0″


In a work that i’m working on, some values of checkboxes and radios have values = 0.
CodeIgniter don’t like them.

Found the solution for it here.

FYI – I fixed this bug. I dont know how to do pull requests – but you need to change Form_validation line 825:

from: if (($field == ” OR $value == ”) OR ($field != $value))
to: if (($field === ” OR $value === ”) OR ($field != $value))

Otherwise it doesnt evaluate the 0 correctly.

You probably also need to do it to lines 781 and 869 (set_select() and set_checkbox() )- but I havent tested it

By TheShiftExchange

CodeIgniter, dompdf-master and php-font-lib

In a project for a non-lucrative organization, we need to implement a print to pdf.

rock ssd

A PHP Error was encountered

Severity: Warning Message: require_once(/home/creaftpu/subdomains/stocks/system/helpers/dompdf/lib/php-font-lib/classes/font.cls.php) [function.require-once]: failed to open stream: No such file or directory Filename: dompdf/ Line Number: 335 Fatal error: require_once() [function.require]: Failed opening required '/home/creaftpu/subdomains/stocks/system/helpers/dompdf/lib/php-font-lib/classes/font.cls.php' (include_path='.:/usr/lib/php:/usr/local/lib/php') in/home/creaftpu/subdomains/stocks/system/helpers/dompdf/ on line 335

We will use dompdf in codeigniter BUT the file that I’v downloaded from GitHub doesn’t has all the files that we need. It’s missing all the files of php-font-lib. So we had to download it and uploaded to the respective folder, to, to have dompdf working in codeigniter you might have to download php-font-lib.