[CALCITE-1414] Add RAND_INTEGER function, which returns a random integer modulo N

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.11.0
• Labels: newbie
• Assignee: Julian Feinauer
• Reporter: Julian Hyde
• Created: 05/Oct/16 18:12
• Updated: 06/Jan/17 19:30
• Resolved: 20/Dec/16 20:03

Description

Add a RANDOM function.
It is not standard SQL, but most DBMSs have one, and it be useful.

It will also allow us to better test non-deterministic expressions.

I propose that:

• RANDOM(n) returns an integer between 0 and n - 1 inclusive.
• There is no facility to specify a seed at this time.
• The random number generator is randomly seeded at query start time based on (say) the method used by Java's new Random(); if you run the query twice, you will (probably) not get the same results.
• If you call the function twice in the same row, it will (probably) return different results.

Issue Links

• is depended upon by: CALCITE-1547 Release Calcite 1.11.0
• relates to: CALCITE-1396 isDeterministic only explores top RexCall
• links to: PR 339