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
