15.8 has no exact binary representation, so a test for equality will fail. Do not use floating point if you want to test for equality. Try DECIMAL
Miguel Figueiredo wrote: >Hello all, > >I have a (probably dumb) question. >My table "temperatura" has two fields described bellow. > >mysql> describe temperatura; >+-------------+----------+------+-----+---------+-------+ >| Field | Type | Null | Key | Default | Extra | >+-------------+----------+------+-----+---------+-------+ >| datetime | datetime | YES | | NULL | | >| temperatura | float | YES | | NULL | | >+-------------+----------+------+-----+---------+-------+ >2 rows in set (0.00 sec) > > >When I try to select rows with floats, the result is an empty set. >For example: > >mysql> select datetime,temperatura from temperatura where >datetime="2002-02-08 09:30:00"; >+---------------------+-------------+ >| datetime | temperatura | >+---------------------+-------------+ >| 2002-02-08 09:30:00 | 15.8 | >+---------------------+-------------+ >1 row in set (0.00 sec) > >----------------------------> got one row :) > >mysql>select datetime,temperatura from temperatura where datetime="2002-02-08 >09:30:00" and temperatura=15.8; > >Empty set (0.00 sec) > >----------> same thing but with the temperatura value, gives me an empy set :( > >When I try to select another row but the temperatura field has an integer >this is what happens: > >mysql> select datetime,temperatura from temperatura where >datetime="2002-01-25 09:40:00"; >+---------------------+-------------+ >| datetime | temperatura | >+---------------------+-------------+ >| 2002-01-25 09:40:00 | 16 | >+---------------------+-------------+ >1 row in set (0.00 sec) > >-----------> got one row :) > >mysql> select datetime,temperatura from temperatura where >datetime="2002-01-25 09:40:00" and temperatura=16; >+---------------------+-------------+ >| datetime | temperatura | >+---------------------+-------------+ >| 2002-01-25 09:40:00 | 16 | >+---------------------+-------------+ >1 row in set (0.00 sec) > >--------------> It works now :/ > >Does anyone have an idea why this happens? How can I select float numbers? > >Best wishes, > >Miguel > --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
