It's an interesting question. But I also don't know how to do it in PostgreSQL. But I figured out alternative solutions.
GNU Grep: grep -E '(hello)[[:blank:]]+\1' <<<'one hello hello world' ripgrep: rg '(hello)[[:blank:]]+\1' --pcre2 <<<'one hello hello world' On Wed, Feb 2, 2022 at 8:53 PM David G. Johnston <david.g.johns...@gmail.com> wrote: > On Wed, Feb 2, 2022 at 1:00 AM Shaozhong SHI <shishaozh...@gmail.com> > wrote: > >> This link is interesting. >> >> regex - Regular Expression For Duplicate Words - Stack Overflow >> <https://stackoverflow.com/questions/2823016/regular-expression-for-duplicate-words> >> >> Is there any example in Postgres? >> >> > Not that I'm immediately aware of, and I'm not going to search the > internet for you. > > The regex capabilities in PostgreSQL are pretty full-featured so a > solution should be possible. You should try translating the SO post > concepts into PostgreSQL yourself and ask specific questions if you get > stuck. > > David J. > >
