Yesterday a colleague was struguling how to compare many fields and many records as a "unit test". A simple solution came up in my mind and i worked.
Gel all the data using GROUP_CONCAT( field1, field2, etc ) as concat_fields
SELECT GROUP_CONCAT( field1, field2) as concatString FROM companies
After that get it with PHP and md5 on concatString and here is 2-3 line for comparing many fields and records to check if there is a change.
$query = 'SELECT GROUP_CONCAT( field1, field2) as concatString FROM companies'; $result = mysql_query($query); $data = mysql_fetch_assoc($result); $hash = md5($data['concatString ']);
example output of $hash is something like : 59458e11692fec53eb1633d2dacf10f9