Re: Query precision issue - Mailing list pgsql-general

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Subject Re: Query precision issue
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Msg-id AANLkTi=Uu-R0-o8-jSAA9hYCXH3VGAyJe722zCEs1Q-g@mail.gmail.com
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In response to Query precision issue  (Sairam Krishnamurthy <kmsram420@gmail.com>)
List pgsql-general
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:
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

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