Question

I have below information in table and want to retrive the count if difference between two dates is >= 1.

Id  testdate  exdate    
1   20120502  20120501  --> This should included, because diff is 1    
2   20120601  20120601  --> This should not included, because diff is 0    
3   20120704  20120703  --> This should included, because diff is 1    
4   20120803  20120802  --> This should included, because diff is 1

Based on the above data, my select count should return 3.

I am trying the following, but it’s not giving any results:

select count(to_char(testdate,'YYYYMMDD')-to_char(exdate,'YYYYMMDD')) from test ;

Answer 1

select count(*)
  from my_table
 where testdate <> exdate 

You really should convert those to a date data-type though… it saves a lot of problems in the long run.

Your query will give you results. It will return 4. It gives you results because as long as the result of testdate - exdate is not null it will return a value for that row.

However, as you’re not using dates Oracle will most probably convert those to numbers, which won’t help for date comparisons should you do that in the future.

20120901 - 20120831 = 70 -- not 1

---

Okay, from your comment:

Working with ,if i use down voteaccept select count(*) from test where
to_char((testdate,’YYYYMMDD’) – to_char(exdate,’YYYYMMDD’)) >= 1; .But
count is one of the column.how to retrive above select statement as
one of the column

you’re trying something completely different.

Your dates are actually dates; it’s helpful to post this. You’re looking for an analytic function, specifically count().

select a.*, count(*) over ( partition by 1 ) as ct
  from my_table a
 where trunc(exdate) <> trunc(testdate)

Note the trunc function, which, without additional parameters will remove the time portion of the date this enabling a direct comparison without resorting to converting the date to a character.