Query precision issue
All,
I have simple query like 'select * from table1 where
column1=-107.6898780000'. This returns an empty set. But there is data
corresponding to this value of column.
When I looked more into it, it seems like a precision issue. The value
for column1 is -107.689878.
More interesting is that the following query fetches the row,
'select * from table1 where column1=-107.689878000'
Note that there are only three trailing zeros in the second query while
there were four in the first.
Can somebody help me to find out the problem? I can very well truncate
the trailing zeros when querying, but I am interested in finding why an
additional trailing zero returns an empty set.
--
Thanks,
Sairam Krishnamurthy
+1 612 859 8161
Hello Sairam,
What is the type of the colum?, what version of postgres are you using?
I didn't had any problem retrieving data in both ways... check out the below
=============================================
test=# create temp table test (col1 float);
CREATE TABLE
test=# insert into test values(-107.689878);
INSERT 0 1
test=# select * from test where col1=-107.6898780000;
col1
-------------
-107.689878
(1 row)
test=# select * from test where col1=-107.689878000;
col1
-------------
-107.689878
(1 row)
test=# select * from version();
version
------------------------------------------------------------------------------------------------------------------
PostgreSQL 8.4.1 on x86_64-redhat-linux-gnu, compiled by GCC gcc (GCC)
4.1.2 20071124 (Red Hat 4.1.2-42), 64-bit
(1 row)
============================================
Thanks
Deepak
On Mon, Oct 25, 2010 at 10:11 AM, Sairam Krishnamurthy
<kmsram420@gmail.com>wrote:
Show quoted text
All,
I have simple query like 'select * from table1 where
column1=-107.6898780000'. This returns an empty set. But there is data
corresponding to this value of column.When I looked more into it, it seems like a precision issue. The value for
column1 is -107.689878.More interesting is that the following query fetches the row,
'select * from table1 where column1=-107.689878000'
Note that there are only three trailing zeros in the second query while
there were four in the first.Can somebody help me to find out the problem? I can very well truncate the
trailing zeros when querying, but I am interested in finding why an
additional trailing zero returns an empty set.--
Thanks,
Sairam Krishnamurthy
+1 612 859 8161