Question

I’ve a database which has four tables, for the sake of simplicity, I will call them table1, table2, table3, table4

Each table has different information but they all share a unique id, sessionid.

I’ve exportet all four tables through my PHPMyAdmin in PHP arrays. This gives me a file called mydomain.php.

Inside this, the data structure is as such:

$table1 = array(
  array('id'=>1,'sessionid'=>'12','field1_1'=>'data','field2_1'=>'data','field3_1'=>'data, 'done'=>1),
  array('id'=>2,'sessionid'=>'13','field1_1'=>'data','field2_1'=>'data','field3_1'=>'data, 'done'=>0)
);

$table2 = array(
  array('id'=>4,'sessionid'=>'12','field1_2'=>'data','field2_2'=>'data','field3_2'=>'data),
  array('id'=>6,'sessionid'=>'13','field1_2'=>'data','field2_2'=>'data','field3_2'=>'data)
);

$table3 = array(
  array('id'=>2,'sessionid'=>'12','field1_3'=>'data','field2_3'=>'data','field3_3'=>'data),
  array('id'=>5,'sessionid'=>'13','field1_3'=>'data','field2_3'=>'data','field3_3'=>'data)
);

$table4 = array(
  array('id'=>6,'sessionid'=>'12','field1_4'=>'data','field2_4'=>'data','field_43'=>'data),
  array('id'=>1,'sessionid'=>'13','field1_4'=>'data','field2_4'=>'data','field3_4'=>'data)
);

My wish is to display them according to their session id (as you can see, the id’s of each table can vary), and I want to check if the field ‘done’ in the first table is set to 1 or 0 and skip fields which are empty or has “NULL” in them.

I’ve tried some different methods, such foreach loops nested in each other but I don’t quite seem to work.

Hope for your help on how to solve this.

Sincere
– Mestika

Answer 1

Why don’t you use SQL? This language is designed to do things like this.

• Use JOIN statement to merge the content of the four tables.
• Use SELECT statement to retrieve the field [done].
• Use WHERE to filter empty strings and NULL values.

And finally, use PHP and the mySQL features to retrieve the table values directly instead of using phpMyAdmin to export the data.

Sample SQL statement:

SELECT t1.sessionid, t1.done
FROM table1 AS t1
JOIN table2 AS t2 ON t1.sessionid = t2.sessionid
JOIN table3 AS t3 ON t2.sessionid = t3.sessionid
JOIN table4 AS t4 ON t3.sessionid = t4.sessionid
WHERE t1.done IS NOT NULL

PHP resources:

• MySQL Improved Extension
• PDO_MYSQL