pgSQL date field Conparison?

Question

Hi all,

I have a pgsql database , i want to compare two fields with there timestamp values.

basic query

select t1.valu1, t1.value2 from table1 as t1 where t1.valu1 == t1.valu2

With TimeStamp comparison

select t1.valu1, t1.value2 from table1 as t1 where EXTRACT(EPOCH FROM TIMESTAMP WITH TIME ZONE  t1.valu1 ) ==  EXTRACT(EPOCH FROM TIMESTAMP WITH TIME ZONE  t1.valu2 ) 

the sample values of valu1 is "14:50:15", "10:50:15" and valu2 "11:10:15", "17:50:15"

I want to convert the valu1 and valu2 to timestamps and after that compare two timestamps

// syntax of extract
EXTRACT(EPOCH FROM TIMESTAMP WITH TIME ZONE '20:38:18');

I Got Error in the following format

EXTRACT(EPOCH FROM TIMESTAMP WITH TIME ZONE  t1.valu2 ) 

Answer 1

You have to give, at least, a day, e.g.:

select EXTRACT(EPOCH FROM '2010-07-05 20:38:18'::timestamptz);

gives

 date_part
------------
 1278358698