$re = '/# Time.*?root.*?(?!# Time)/s';
$str = '# Time: 230706 17:12:48
# User@Host: sample[sample] @ localhost []
# Thread_id: 626784 Schema: sample QC_hit: No
# Query_time: 2.976557 Lock_time: 0.000178 Rows_sent: 0 Rows_examined: 3344231
# Rows_affected: 0 Bytes_sent: 195
SET timestamp=1688677968;
SELECT * from a;
# Time: 230706 17:15:51
# User@Host: root[root] @ localhost []
# Thread_id: 627770 Schema: sample QC_hit: No
# Query_time: 2.581676 Lock_time: 0.000270 Rows_sent: 0 Rows_examined: 2432228
# Rows_affected: 0 Bytes_sent: 195
SET timestamp=1688678151;
select * from cs;
# Time: 230706 17:13:37
# User@Host: sample[sample] @ localhost []
# Thread_id: 627027 Schema: oiemorug_wp598 QC_hit: No
# Query_time: 3.901325 Lock_time: 0.000145 Rows_sent: 0 Rows_examined: 3851050
# Rows_affected: 0 Bytes_sent: 195
SET timestamp=1688678017;
SELECT * from b
# Time: 230706 17:15:51
# User@Host: root[root] @ localhost []
# Thread_id: 627770 Schema: sample QC_hit: No
# Query_time: 2.581676 Lock_time: 0.000270 Rows_sent: 0 Rows_examined: 2432228
# Rows_affected: 0 Bytes_sent: 195
SET timestamp=1688678151;
select * from cs';
preg_match_all($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