SIGN

Return the sign of a number:
  • 0 = the number is 0.
  • 1 = the number is a positive number
  • -1 = the number is a negative number
SIGN(number)
For example:
premdb=# SELECT SIGN(-52.3);
 sign 
------
   -1
(1 row)
The following example finds the sign of the result of an expression.
premdb=# SELECT ftscore, 
SIGN((SUBSTR(ftscore,1,1)::INT)-(SUBSTR(ftscore,3,1)::INT)) 
FROM match LIMIT 25;
 ftscore | sign 
---------+------
 0-1     |   -1
 0-1     |   -1
 2-1     |    1
 3-0     |    1
 3-0     |    1
 2-0     |    1
 0-0     |    0
 0-0     |    0
 0-1     |   -1
 1-0     |    1
 0-1     |   -1
 1-1     |    0
 2-4     |   -1
...