Re: Regular expressions

"Tumurbaatar S." <tumurbaatar@datacom.mn> writes:
> 2. 2 or more of same char
> how the 2nd's pattern should be look?

I think you need a back reference:

regression=# select 'abc' ~ '(.)\\1';
 ?column?
----------
 f
(1 row)

regression=# select 'abb' ~ '(.)\\1';
 ?column?
----------
 t
(1 row)

            regards, tom lane