Note that https://issues.apache.org/jira/browse/CALCITE-1794 <https://issues.apache.org/jira/browse/CALCITE-1794> deals with very similar expressions (albeit with CAST, and optimized using SARGs rather than RexSimplify) and was just fixed today.
> On Mar 2, 2022, at 4:52 PM, Benchao Li <libenc...@apache.org> wrote: > > Hi xiong, > > For the simplification result below: > # "a <> 1 or a = 1 [a is nullable]" > 1. UNKNOWN AS UNKNOWN: OR(IS NOT NULL(a), null) > 2. UNKNOWN AS TRUE: TRUE > 3. UNKNOWN AS FALSE: IS NOT NULL(a) > > # "a<>1 and a = 2 [a is nullable]" > 1. UNKNOWN AS UNKNOWN: =(a, '2') > 2. UNKNOWN AS TRUE: =(a, '2') > 3. UNKNOWN AS FALSE: =(a, '2') > > IMHO, this is expected and correct. > For the first case, the result can be simplified to: > if a is null: > null > else: > true > then, for each unknown value, we can evaluate to the results above > correspondingly. > > For the second case, the result is also correct, we can simplify `a<>1 and > a = 2` to `a = 2` regardless of nullability of a, > and `=(a, '2')` is the simplest form. > > xiong duan <nobigo...@gmail.com> 于2022年2月28日周一 10:26写道： > >> Hi followers. >> When I learned how to simplify the Rexnode in Calcite. I meet a problem >> and need some help. >> For example: >> When we simplify "a <> 1 or a = 1 [a is nullable]", (the result is >> different according to how to treat the UNKNOW value) : >> >> checkSimplify3_( or(ne(vInt(0), literal(1)), eq(vInt(0), >> literal(1))), "OR(IS NOT NULL(?0.int0), null)", "IS NOT >> NULL(?0.int0)", "true"); >> >> But when I try to simplify "a<>1 and a = 2 [a is nullable]": >> >> checkSimplify3_( >> and(ne(vInt(0), literal(1)), >> eq(vInt(0), literal(2))), >> "=(?0.int0, 2)", >> "=(?0.int0, 2)", >> "=(?0.int0, 2)"); >> >> And I think this result should be: >> "a<>1 and a = 2 [a is nullable]": >> >> UNKNOW AS TRUE: a IS NULL or a = 2 >> UNKNOW AS FALSE: a is NOT NULL and a =2 >> UNKNOW AS UNKNOW: CASE(IS NULL(a), null, a = 2) >> >> So What did I misunderstand? It is a bug or intentional? Any feedback would >> be appreciated. >> > > > -- > > Best, > Benchao Li
