[CALCITE-2620] Simplify "coalesce(null,x)" to "x"

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.18.0
• Fix Version/s: 1.18.0
• Component/s: core
• Assignee: pengzhiwei
• Reporter: pengzhiwei
• Created: 11/Oct/18 08:28
• Updated: 27/Feb/24 22:24
• Resolved: 17/Oct/18 20:50

Description

"coalesce(x0,x1,.....)" can be simplified if any of "xi" is null literal.

e.g.  "coalesce(null,x)" can simplify to "x", "coalesce(x,null,y)" can simplify to "coalesce(x,y)"

Issue Links

• links to: PR 882