[Firebird-devel] [ firebird-Bugs-489023 ] incorrect work of equation operator

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

Bugs item #489023, was opened at 2001-12-04 11:16
You can respond by visiting: 
http://sourceforge.net/tracker/?func=detail&atid=109028&aid=489023&group_id=9028

Category: Core Engine
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Andrei Kireev (andreik)
Assigned to: Nobody/Anonymous (nobody)
Summary: incorrect work of equation operator

Initial Comment:

There is a bug in FB RC1 build 608 with equation 
operator
and varchar/char fields.

Below is a step-by-step example which shows incorrect
behavior.


1. create table s (f varchar(10))

2. insert into s values ('aaa')

   take care, that there are just three charactes
   no leading or trailing spaces

3. select * from s
   
   F
   ==========
   aaa

   Ok!

4. select * from s where f = 'aaa'

   F
   ==========
   aaa

   All right.


5. select * from s where f = 'aaa '  <-- look, there 
is a trailing blank

   Result is incorrect!

   F
   ==========
   aaa

   field defined as varchar, not char! so, 'aaa' 
<> 'aaa '
   at least, in Delphi, C++ or VB that is true.

6. insert into s values ('aaa ')

7. select * from s

   F
   ==========
   aaa
   aaa

   Ok

8. select * from s where f = 'aaa'

   The result is incorrect again:

   F
   ==========
   aaa
   aaa

9. select * from s where f 
= 'aaa                                    '

   F
   ==========
   aaa
   aaa

   The result is incorrect.
   And look, cpecified string exceeds length of field 
varchar(10).

10. LIKE without charactes % or _ must behave the same 
way as
   quation operator =, isn't it?

   so try,

   select * from s where f like 'aaa'

   wow! result is CORRECT this time:

   F
   ==========
   aaa

11. select * from s where f like 'aaa '  

   again correct:

   F
   ==========
   aaa

12.select * from s where f like 'aaa%'      

   F
   ==========
   aaa
   aaa

   it's Ok

13.select * from s where f containing 'aaa' 

   F
   ==========
   aaa
   aaa

   it's Ok

14.select * from s where f containing 'aaa '    

   F
   ==========
   aaa

   Ok!

so, the equation operator with strings gets wrong 
results.
It strips trailing spaces from field values as well as 
from
specified string to match.

In those cases LIKE operator or CONTAINING results in 
correct
values.

Result of LIKE comparison != result of = operator
if field contains trailing spaces and LIKE string to 
match
does not contain '%' or '_'


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

You can respond by visiting: 
http://sourceforge.net/tracker/?func=detail&atid=109028&aid=489023&group_id=9028