widening conversions for CAST

Author: mspruc

wayang-api/wayang-api-sql/src/main/java/org/apache/wayang/api/sql/calcite/converter/functions/FilterPredicateImpl.java

@@ -57,7 +57,7 @@ public SerializableFunction<List<Object>, Object> deriveOperation(final SqlKind
                 case MINUS -> widenToDouble.apply(input.get(0)) - widenToDouble.apply(input.get(1));
                 case PLUS -> widenToDouble.apply(input.get(0)) + widenToDouble.apply(input.get(1));
                 // TODO: may need better support for CASTing in the future. See sqlCast() in this file.
-                case CAST -> ensureComparable.apply(input.get(0));
+                case CAST -> input.get(0) instanceof Number ? widenToDouble.apply(input.get(0)) : ensureComparable.apply(input.get(0));
                 case SEARCH -> {
                     if (input.get(0) instanceof final ImmutableRangeSet range) {
                         assert input.get(1) instanceof Comparable