MOD

Return the remainder for a division operation, where the first parameter is divided by the second.

MOD(number, number)
Both number expressions must evaluate to integer or DECIMAL values.
For example:
premdb=# select mod(22, 21.234) from sys.const;
  mod  
-------
 0.766
(1 row)

premdb=# select name, mod(avg_att,capacity) from team where capacity>0 order by 2 desc;
          name           |  mod   
-------------------------+--------
 Manchester United       | 75.286
 Arsenal                 | 59.944
 Manchester City         | 54.041
 Newcastle United        | 49.754
 Liverpool               | 43.910
 Sunderland              | 43.071
...

premdb=# select seasonid, season_name from season where mod(seasonid,2)=1 order by 1,2;
 seasonid | season_name 
----------+-------------
        1 | 1992-1993
        3 | 1994-1995
        5 | 1996-1997
        7 | 1998-1999
        9 | 2000-2001
       11 | 2002-2003
       13 | 2004-2005
       15 | 2006-2007
       17 | 2008-2009
       19 | 2010-2011
       21 | 2012-2013
       23 | 2014-2015
       25 | 2016-2017
(13 rows)