$re = '/\'(?P<ts>\d{4}-\d\d-\d\dT\d\d:\d\d:\d\dZ).*?\bdb=(?P<db>\S*).*?\buser=(?P<user>\S*).*?LOG:\s+(?P<query>.*?);?$/m';
$str = '\'2022-05-08T04:18:43Z UTC [ db=dev user=test pid=1073922359 userid=100 xid=2063 ]\' LOG: alter table my_table alter column string type varchar(16);';
preg_match_all($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