$re = '/\b\w*?[dD]ate\w*?\b/m';
$str = 'Expected_Start_DateTime,Metrics_Count,Device_UID,Command_Name,Command_Interval,Start_DateTime,Instance_UID,Execution_Date,Metrics_Size_KB,End_DateTime,Tags_Countfrom command_execution';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php