Julian Hyde created CALCITE-4170: ------------------------------------ Summary: Improve simplification of "<>" predicates Key: CALCITE-4170 URL: https://issues.apache.org/jira/browse/CALCITE-4170 Project: Calcite Issue Type: Bug Reporter: Julian Hyde
Improve simplification of "<>" (not equals) predicates. Today we can simplify "a = 1 or a <> 1" to "true" but we cannot simplify "a <> 1 or a = 1" to "true". The problem is this. The algorithm for simplifying "or" builds a up a list of predicates as it works left to right. After dealing with "a = 1" RexSimplifier has a predicate "a = 1" and therefore it can simplify the next predicate to anything that returns the right result over the possible inputs - which will not include a = 1 - and therefore 'a <> 1' can be simplified to 'true'. But today, we can't take that approach with "a <> 1 or a = 1" because "a <> 1" cannot be represented as a single range. It needs two ranges - less than 1 or greater than 1. The fix is therefore to allow predicates to be range sets not just ranges. -- This message was sent by Atlassian Jira (v8.3.4#803005)