Re: log() in sqlite3
Peng Yu <[email protected]>
| Newsgroups | gmane.comp.db.sqlite.general |
|---|---|
| Message-ID | <CABrM6w=eMDgb4UFjE5YY=Tj3GzrJ_bKf+FVOQwu=nrp7Gjwm4w@mail.gmail.com> |
How to use extension-functions.c? It means that I have to compile it? How to use it with python? For python, create_function should be a better solution? Thanks. On 1/31/20, Chris Brody <[email protected]> wrote: > The log function does seem to be supported by extension-functions.c which > is available from here: https://www.sqlite.org/contrib > > On Fri, Jan 31, 2020 at 1:30 PM David Raymond <[email protected]> > wrote: > >> The core functions of the library are fairly unlikely to get expanded upon >> at this point, so it's up to the application using the SQLite library to >> expand on them. >> >> You can load an extension which has those functions. Or the C API gives >> you means to add your own functions. >> >> For Python, the built in sqlite3 module has the create_function() method >> for a connection which will register a function. >> >> https://docs.python.org/3.8/library/sqlite3.html#sqlite3.Connection.create_function >> >> Once you register the function you can use it right in your sql text like >> any other function, >> "update tbl set field2 = log(field1);" >> >> And you don't need to do the more tedious: >> a) Get original data with statement 1 >> b) Do calculations in the outside program >> c) Use the result in statement 2 >> >> >> -----Original Message----- >> From: sqlite-users <[email protected]> On >> Behalf Of Peng Yu >> Sent: Friday, January 31, 2020 12:42 PM >> To: SQLite mailing list <[email protected]> >> Subject: [sqlite] log() in sqlite3 >> >> Hi, >> >> I see that many math functions (like log()) are not in sqlite3. It >> seems that SQL standard doesn't have them. >> >> https://www.sqlite.org/lang_corefunc.html >> >> But since sqlite3 contains non-standard functions anyway. Would it be >> considered to add those functions? >> >> Given the current version of sqlite3, is the only choice of computing >> log() to get the data into another language (e.g., python) and compute >> the log over there? Thanks. >> >> -- >> Regards, >> Peng >> _______________________________________________ >> sqlite-users mailing list >> [email protected] >> http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users >> _______________________________________________ >> sqlite-users mailing list >> [email protected] >> http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users >> > _______________________________________________ > sqlite-users mailing list > [email protected] > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > -- Regards, Peng _______________________________________________ sqlite-users mailing list [email protected] http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users