Re: window function to sort times series data?

In going through the arcana of string functions, I have come across the following series of selects that contain, for
me,a mysterious "$re$".<br /><br />-- return all matches from regexp<br />SELECT regexp_matches('foobarbequebaz',
$re$(bar)(beque)$re$);<br/><br />-- test case insensitive<br />SELECT regexp_matches('foObARbEqUEbAz',
$re$(bar)(beque)$re$,'i');<br /><br />-- global option - more than one match<br />SELECT
regexp_matches('foobarbequebazilbarfbonk',$re$(b[^b]+)(b[^b]+)$re$, 'g');<br /><br />When I run this I get:<br /><br
/>regexp_matches<br/>--------------------------<br /><Unknown(2,003)><br /><br />I have not been able to find out
whatit all means.  Forgive me for my blindness.<br /><br />John<br /><br />P.S. The author of the statements is "alexk"
atCommand Prompt.  They are test statements against Postgres' string functions.<br />