In yesterday’s tip we learned that we can use the SEEDED_RANDOM function to re-use generated numbers. There is not a SEEDED_RANDOMINT function, but that’s not a problem. Create your own!
Example:
dbadmin=> SELECT random() random1, random() random2, random() random3;
random1 | random2 | random3
-------------------+-------------------+-------------------
0.206615947652608 | 0.308142327470705 | 0.124399376800284
(1 row)
dbadmin=> SELECT seeded_random(1) random1, seeded_random(1) random1,
dbadmin-> seeded_random(2) random2, seeded_random(2) random2;
random1 | random1 | random2 | random2
-------------------+-------------------+------------------+------------------
0.417021998437122 | 0.417021998437122 | 0.43599490262568 | 0.43599490262568
(1 row)
dbadmin=> CREATE OR REPLACE FUNCTION seeded_randomint (x INT, y INT) RETURN INT
dbadmin-> AS
dbadmin-> BEGIN
dbadmin-> RETURN FLOOR(SEEDED_RANDOM(x)*(y));
dbadmin-> END;
CREATE FUNCTION
dbadmin=> SELECT seeded_randomint(1, 100) random1, seeded_randomint(1, 100) random1,
dbadmin-> seeded_randomint(2, 100) random2, seeded_randomint(2, 100) random2;
random1 | random1 | random2 | random2
---------+---------+---------+---------
41 | 41 | 43 | 43
(1 row)
Helpful Links:https://www.vertica.com/docs/latest/HTML/Content/Authoring/SQLReferenceManual/Functions/Mathematical/RANDOM.htm https://www.vertica.com/docs/latest/HTML/Content/Authoring/SQLReferenceManual/Functions/Mathematical/RANDOMINT.htm
Have fun!
About the Author
James Knicely
Vertica Field Chief Technologist
I've had the privilege of working with many database technologies in my career. But after being introduced to Vertica in May of 2011 as a client, I was hooked on the new technology after witnessing a query run in milliseconds that had previously ran for hours on the legacy database we had in place. It was then that I knew I wanted to eventually join the Vertica team, and 4 years later I did! I am currently a Vertica evangelist and am ready to help you get on board! Please feel free to reach out to me with any questions you have about Vertica and make sure to follow my Vertica Quick Tips!
