gianm commented on code in PR #14976:
URL: https://github.com/apache/druid/pull/14976#discussion_r1326114443
##########
processing/src/main/java/org/apache/druid/math/expr/Function.java:
##########
@@ -2224,6 +2224,89 @@ public <T> ExprVectorProcessor<T>
asVectorProcessor(Expr.VectorInputBindingInspe
}
}
+ /**
+ * SQL function "x IS NOT DISTINCT FROM y". Very similar to "x = y", i.e.
{@link BinEqExpr}, except this function
+ * never returns null, and this function considers NULL itself to be
not-distinct-from NULL.
+ */
+ class IsNotDistinctFromFunc implements Function
+ {
+ @Override
+ public String name()
+ {
+ return "notdistinctfrom";
+ }
+
+ @Override
+ public ExprEval apply(List<Expr> args, Expr.ObjectBinding bindings)
+ {
+ final ExprEval leftVal = args.get(0).eval(bindings);
+ final ExprEval rightVal = args.get(1).eval(bindings);
+
+ if (leftVal.value() == null || rightVal.value() == null) {
+ return ExprEval.ofLongBoolean(leftVal.value() == null &&
rightVal.value() == null);
+ }
+
+ final ExpressionType comparisonType =
ExpressionTypeConversion.autoDetect(leftVal, rightVal);
+ switch (comparisonType.getType()) {
+ case STRING:
+ return ExprEval.ofLongBoolean(Objects.equals(leftVal.asString(),
rightVal.asString()));
+ case LONG:
+ return ExprEval.ofLongBoolean(leftVal.asLong() == rightVal.asLong());
+ case DOUBLE:
+ default:
+ if (leftVal.isNumericNull() || rightVal.isNumericNull()) {
+ return ExprEval.ofLongBoolean(leftVal.isNumericNull() &&
rightVal.isNumericNull());
Review Comment:
I thought this part was weird too, but didn't change it (just copied and
adapted the code for `==`). I added this comment to make it clear where the
code comes from:
```
// Code copied and adapted from BinaryBooleanOpExprBase and BinEqExpr.
// The code isn't shared due to differences in code structure:
BinaryBooleanOpExprBase + BinEqExpr have logic
// interleaved between parent and child class, but we can't use
BinaryBooleanOpExprBase as a parent here, because
// (a) this is a function, not an expr; and (b) our logic for handling
and returning nulls is different from most
// binary exprs, where null in means null out.
```
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