[CALCITE-1289] RexUtil.simplifyCase() should account for nullability

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.9.0
• Component/s: core
• Assignee: Julian Hyde
• Reporter: MinJi Kim
• Created: 11/Jun/16 01:20
• Updated: 27/Feb/24 22:23
• Resolved: 15/Jun/16 17:47

Description

RexUtil.simplify() returns incorrect type information if the RexNode is a CASE(CONDITION, TRUE, FALSE). In this case, the CASE RexNode is a Boolean with isNullable == false. But, with the simplify, RexUtil.simplify returns CONDITION. When CONDITION has isNullable == true, the returned RexNode does not match the row type and fails to transform (vice versa).