Re: [SQL] Extracting hostname from URI column
Paul Lambert wrote: > Andrej Ricnik-Bay wrote: > >> Plain regex The key are the parenthesis () ... >> basically it will omit ANYTHING + two slashes at the beginning >> of a string. Then it will match everything BUT a slash, and as >> much of that as possible since regex are greedy by default >> (hence the host name he was looking for) ... and everything >> AFTER a slash will be omitted. >> Cheers, >> Andrej > Thanks - that makes a bit more sense. I'm in the middle of reading chapter > 9.3.7 of the manual - POSIX Regular Expressions - which I'm assuming is > dealing with this, so it's looking clearer. A very good resource on regular expressions is "Mastering Regular Expressions" by Jeffrey Friedl, now in its third edition: http://www.oreilly.com/catalog/regex3/ I read the first ed. years ago and it was very illuminating. -- Alvaro Herrera Developer, http://www.PostgreSQL.org/ "Acepta los honores y aplausos y perderás tu libertad" ---(end of broadcast)--- TIP 7: You can help support the PostgreSQL project by donating at http://www.postgresql.org/about/donate
Re: [SQL] Simple Query?
Koen Bok escreveu: I am doing some optimization on our search, but I need some advise... table: item idname -- 1iPod 2Zune 3Walkman table: search_item id_searchid_item -- 11 12 13 22 23 31 33 Now what I want to have is the items that match with id_search 1 and 2 and 3. Therefore I use the following SQL query. SELECT * FROM item WHERE id IN (SELECT id_item FROM search_item WHERE id_search=1 AND id_item IN (SELECT id_item FROM search_item WHERE id_search=2 AND id_item IN (SELECT id_item FROM search_item WHERE id_search=3))); This should only return id_item 3. Would this be the best SQL query to get this result? I have the feeling there should be something better, but I cannot find it. Anyone has a hint? SELECT * FROM item WHERE id IN (SELECT id_item FROM search_item WHERE id_search=1 INTERSECT SELECT id_item FROM search_item WHERE id_search=2 INTERSECT SELECT id_item FROM search_item WHERE id_search=3); Osvaldo ---(end of broadcast)--- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
