When I started my test, I turn off my app. And do update(and select) using only ISQL tool (IBExpert) and dbweaver. in both I had to configure select to show float using mask (0.######..), so the number can be different that I show you, but always eat last numbers. I need to store long decimals numbers maybe more than 15 decimals, is it possible without store as string?
Em qua., 26 de fev. de 2020 às 15:21, Mark Rotteveel [email protected] [firebird-support] <[email protected]> escreveu: > > > On 2020-02-26 19:07, hamacker [email protected] [firebird-support] > wrote: > > Hi All, > > > > I do this update: > > UPDATE CV SET > > perc_lucro=42.503064336972848 > > WHERE (id_cv=57528) > > > > Then I do a select and 'perc_lucro' was change to 42,5030643369728 > > after updated, two last numbers disappear. > > Why? > > perc_lucro is double precision type. > > FB 3.0.5 32bits, Windows 64. > > A double precision is not an exact numeric type, it has roughly a > precision of 15-17 decimals. Even that isn't entirely correct because of > how a double precision works. In any case, a double precision cannot > exactly store 42.503064336972848. > > However, when testing this (with `select cast(42.503064336972848 as > double precision) from rdb$database`), I get a value of > 42.50306433697285, which suggest that your software may do some > additional rounding or truncation when presenting the value. > > Mark > >
