$re = '/^\s*insert(?:\s+into)?\s+(?<TableName>\[.*?\]|[^ (]+)\s*\((?<Columns>.+?)\)/im';
$str = 'insert into [SomeTable]([Run ID]) values (something, something)
insert [SomeTable]([Run ID]) values (something, something)
insert into [SomeTable]([Run ID]) values (something, something)
insert into SomeTable([Run ID]) values (something, something)
insert SomeTable([Run ID]) values (something, something)
insert into SomeTable([Run ID]) values (something, something)
insert into [Some Table]([Run ID]) values (something, something)
insert [Some Table]([Run ID]) values (something, something)
insert into [Some Table]([Run ID]) values (something, something)
insert into [Some Table] ([Run ID]) values (something, something)
insert [Some Table] ([Run ID]) values (something, something)
insert into [Some Table] ( [Run ID],) values (something, something)
insert into [nGineUnitTests].[dbo].[TestOdbcReadAndWriteTo]([Run ID]) values (something, something)
insert [nGineUnitTests].[dbo].[TestOdbcReadAndWriteTo]([Run ID]) values (something, something)
insert into [nGineUnitTests].[dbo].[TestOdbcReadAndWriteTo]([Run ID]) values (something, something)
insert into [nGineUnitTests].[dbo].TestOdbcReadAndWriteTo([Run ID]) values (something, something)
insert [nGineUnitTests].dbo.TestOdbcReadAndWriteTo ([Run ID]) values (something, something)
insert nGineUnitTests.dbo.TestOdbcReadAndWriteTo ([Run ID]) values (something, something)
insert [nGineUnitTests].dbo.[TestOdbcReadAndWriteTo] ([Run ID]) values (something, something)
insert into [nGine Unit Tests].[dbo].[TestOdbcReadAndWriteTo]([Run ID]) values (something, something)
insert [nGine Unit Tests].[dbo].[TestOdbcReadAndWriteTo]([Run ID]) values (something, something)
insert into [nGine Unit Tests].[dbo].[TestOdbcReadAndWriteTo]([Run ID]) values (something, something)
insert into [nGine Unit Tests].[dbo].[TestOdbcReadAndWriteTo] ([Run ID]) values (something, something)
insert [nGine Unit Tests].[dbo].[TestOdbcReadAndWriteTo] ([Run ID]) values (something, something)
insert into [nGine Unit Tests].[dbo].[TestOdbcReadAndWriteTo] ( [Run ID],) values (something, something)
"This is not an insert statement insert into [dbo].[DoNotAllowNullsString]([Col_umn1]) values (?)"';
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