Re: log() in sqlite3

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
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