On 04 May 2019, at 18:49, Richard Hipp <d...@sqlite.org> wrote: > On 5/4/19, Manuel Rigger <rigger.man...@gmail.com> wrote:
>> Consider the following example: >> >> CREATE TABLE t1 (c0, c1 REAL, PRIMARY KEY (c1, c0)); >> INSERT INTO t1(c1) VALUES (0X7ffffffffffffff);; >> SELECT ALL * FROM t1 WHERE c1 = 5.76460752303423e+17; >> >> I would expect the row to be fetched, which is not the case. > > But 0x7ffffffffffffff != 5.76460752303423e+17. Try it: > > SELECT 0x7ffffffffffffff != 5.76460752303423e+17; > > You should get back 0. > > The rule of thumb is to never expect the == operator to give a > meaningful answer for floating-point numbers. Only use <, <=, >, and >=. My floating-point "don't do that" lesson occured in 1965 when trying to compute square roots by Newton's method. This was on an Elliott 803B. -- Cheers -- Tim _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
