Hi, Besides the most excellent explanation given by Keith Medcalf, I want to point out a couple of (hopefully) helpful things –
1. Contrary to your subject line, SQLite actually does give a feedback/returns something. It is just not good enough (for many of us). Consider the following: ``` ○ → sqlite3 SQLite version 3.30.0 2019-10-04 15:03:17 Enter ".help" for usage hints. Connected to a transient in-memory database. Use ".open FILENAME" to reopen on a persistent database. sqlite> SELECT 30 / 2; 15 sqlite> SELECT 30 / 57; 0 sqlite> SELECT 55 / 0; sqlite> ``` See that blank line after the last operation? That is SQLite “printing” out a NULL value. The `.nullvalue STRING` setting in the command line client can change that blank like to something more visual/meaningful. 2. The `typeof()` operator is super. It is like the detective cousin of CAST(). The latter allows you to change the type of a data value and the former allows you to find out the typeof data. ``` sqlite> SELECT typeof(55 / 0); null sqlite> SELECT typeof(30 / 2); integer sqlite> SELECT typeof(30.0 / 55); real sqlite> SELECT 30.0 / 55; 0.545454545454545 sqlite> ``` Good luck. And nice question as it reminded us of this math idiosyncrasy of SQLite. > On Mar 10, 2020, at 8:21 AM, Octopus ZHANG <zhangysh1...@gmail.com> wrote: > > I try to run a simple math expression, but SQLite gives no feedback : > > sqlite> select 99-(55/(30/57)); > > > > > Should I expect it to return nothing? -- Puneet Kishor Just Another Creative Commoner http://punkish.org/About _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
