[Firebird-devel] [ firebird-Bugs-525560 ] Multiplication returns incorrect result

[<no...@so...>]

Bugs item #525560, was opened at 2002-03-04 11:10
You can respond by visiting: 
http://sourceforge.net/tracker/?func=detail&atid=109028&aid=525560&group_id=9028

Category: Core Engine
>Group: As Designed/Pitfall
>Status: Closed
>Resolution: Invalid
Priority: 5
Submitted By: Eric Gueguiniat (ricolebo)
Assigned to: Nobody/Anonymous (nobody)
Summary: Multiplication returns incorrect result

Initial Comment:
Test : Firebird RC2 - WIN 98

This query return incorect result :

SELECT CAST( A*B AS NUMERIC(15,2)) FROM TEST
--------------------------------------------
2.13  -> FALSE (2.14)
1.04  -> OK

Test : Firebird 338 - WIN 98

SELECT CAST( A*B AS NUMERIC(15,2)) FROM TEST
--------------------------------------------
2.13  -> FALSE (2.14)
1.03  -> FALSE (2.04)

I have tested to IB 6.0 6.5 and i obtain the same 
result. May be it isn't a bug ?
Thanks for your response.

Eric Guéguiniat



The script of the DB is :

SET SQL DIALECT 3;

SET NAMES NONE;

CREATE DATABASE 'c:\test.gdb'
USER 'SYSDBA' PASSWORD 'masterkey'
PAGE_SIZE 4096
DEFAULT CHARACTER SET NONE;

CREATE TABLE TEST (
    ID INTEGER NOT NULL,
    A DOUBLE PRECISION,
    B DOUBLE PRECISION);

INSERT INTO TEST (ID, A, B) VALUES (1, 3.5, 0.61);
INSERT INTO TEST (ID, A, B) VALUES (2, 1.5, 0.69);

COMMIT WORK;

ALTER TABLE TEST ADD CONSTRAINT PK_TEST PRIMARY KEY 
(ID); 

----------------------------------------------------------------------

>Comment By: Sean Leyne (seanleyne)
Date: 2002-03-05 12:41

Message:
Logged In: YES 
user_id=71163

According to Ann Harrision; 

These are the 'natural' results of floating point 
operations.

----------------------------------------------------------------------

You can respond by visiting: 
http://sourceforge.net/tracker/?func=detail&atid=109028&aid=525560&group_id=9028