Both, I guess Insert into ... select a,b,sum(theCount) group by a,b;
-----Ursprüngliche Nachricht----- Von: Simon Slavin [mailto:slav...@bigfraud.org] Gesendet: Mittwoch, 10. Dezember 2014 12:39 An: General Discussion of SQLite Database Betreff: [sqlite] replace many rows with one Dear folks, A little SQL question for you. The database file concerned is purely for data manipulation at the moment. I can do anything I like to it, even at the schema level, without inconveniencing anyone. I have a TABLE with about 300 million (sic.) entries in it, as follows: CREATE TABLE s2 (a TEXT, b TEXT, theCount INTEGER) There are numerous cases where two or more rows (up to a few thousand in some cases) have the same values for a and b. I would like to merge those rows into one row with a 'theCount' which is the total of all the merged rows. Presumably I do something like CREATE TABLE s2merged (a TEXT, b TEXT, theCount INTEGER) INSERT INTO s2merged SELECT DISTINCT ... FROM s2 and there'll be a TOTAL() in there somewhere. Or is it GROUP BY ? I can't seem to get the right phrasing. Also, given that this is the last operation I'll be doing on table s2, will it speed things up to create an index on s2 (a,b), or will the SELECT just spend the same time making its own temporary index ? Simon. _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users ___________________________________________ Gunter Hick Software Engineer Scientific Games International GmbH FN 157284 a, HG Wien Klitschgasse 2-4, A-1130 Vienna, Austria Tel: +43 1 80100 0 E-Mail: h...@scigames.at This communication (including any attachments) is intended for the use of the intended recipient(s) only and may contain information that is confidential, privileged or legally protected. Any unauthorized use or dissemination of this communication is strictly prohibited. If you have received this communication in error, please immediately notify the sender by return e-mail message and delete all copies of the original communication. Thank you for your cooperation. _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
