> create table test( Date datetime); Datetime is not a data type and therefore has numeric affinity.
> insert test now(); sqlite> select now(); Error: no such function: now What is function now and what does it return? > select date+2 as bbb,date-12 as cc from test; > the result is > 2014,2000 >From this I can surmise that your "now()" is the number 2012. > I wanna know how to add any day use sql command First you need to store an application specific representation of the datetime value in the "date" column. Then you apply the function to that value that achieves the result you desire. For example, if you store an MJD value in "Date" then you add or subtract fractional days. If you store a unix-epoch value, then adding/subtracting 86400 moves forward and back a day. There are builtin functions to help with some of this. You might want to refer to: http://www.sqlite.org/datatype3.html and http://www.sqlite.org/lang_datefunc.html --- () ascii ribbon campaign against html e-mail /\ www.asciiribbon.org > -----Original Message----- > From: sqlite-users-boun...@sqlite.org [mailto:sqlite-users- > boun...@sqlite.org] On Behalf Of YAN HONG YE > Sent: Wednesday, 22 August, 2012 20:14 > To: sqlite-users@sqlite.org > Subject: [sqlite] datetime question > > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
