Generate Random Integers, Including Negative Numbers

SarahL

Jim Knicely authored this tip.

The RANDOMINT(n) function returns one of the n integers from 0 through n – 1. Those are all positive integers. What if I want to include negative integers? That’s easy with a simple multiplication.

Example:

dbadmin=> SELECT DECODE(randomint(2), 1, 1, -1) * randomint(11) "Random INT from -10 to 10";
Random INT from -10 to 10
---------------------------
                        -1
(1 row)

dbadmin=> SELECT DECODE(randomint(2), 1, 1, -1) * randomint(11) "Random INT from -10 to 10";
Random INT from -10 to 10
---------------------------
                         3
(1 row)

dbadmin=> SELECT DECODE(randomint(2), 1, 1, -1) * randomint(11) "Random INT from -10 to 10";
Random INT from -10 to 10
---------------------------
                        -7
(1 row)

dbadmin=> SELECT DECODE(randomint(2), 1, 1, -1) * randomint(11) "Random INT from -10 to 10";
Random INT from -10 to 10
---------------------------
                         9
(1 row)

Have fun!