Re: Number of occurrence of characters?
От | hubert depesz lubaczewski |
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Тема | Re: Number of occurrence of characters? |
Дата | |
Msg-id | 20090205141335.GA18324@depesz.com обсуждение исходный текст |
Ответ на | Number of occurrence of characters? (Ivan Voras <ivoras@freebsd.org>) |
Ответы |
Re: Number of occurrence of characters?
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Список | pgsql-performance |
On Thu, Feb 05, 2009 at 02:31:24PM +0100, Ivan Voras wrote: > The problem is how to do it efficiently. I see there isn't a built-in > function that counts character occurrences so I'd have to write it > myself. An additional constraint is that it must be implemented with > built-in capabilities, i.e. SQL and plpsql languages. I can do it the > brute force way, looping over the string and processing one by one > character with substring(), but is there a faster way? # select length(regexp_replace('/some/string/with/slashes', '[^/]+', '', 'g')); length -------- 4 (1 row) depesz -- Linkedin: http://www.linkedin.com/in/depesz / blog: http://www.depesz.com/ jid/gtalk: depesz@depesz.com / aim:depeszhdl / skype:depesz_hdl / gg:6749007
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