private static void splitJoinCondition(
      List<RelDataTypeField> sysFieldList,
      List<RelNode> inputs,
      RexNode condition,
      List<List<RexNode>> joinKeys,
      List<Integer> filterNulls,
      List<SqlOperator> rangeOp,
      List<RexNode> nonEquiList) throws CalciteSemanticException {
    final int sysFieldCount = sysFieldList.size();
    final RelOptCluster cluster = inputs.get(0).getCluster();
    final RexBuilder rexBuilder = cluster.getRexBuilder();

    if (condition instanceof RexCall) {
      RexCall call = (RexCall) condition;
      if (call.getOperator() == SqlStdOperatorTable.AND) {
        for (RexNode operand : call.getOperands()) {
          splitJoinCondition(
              sysFieldList,
              inputs,
              operand,
              joinKeys,
              filterNulls,
              rangeOp,
              nonEquiList);
        }
        return;
      }

      RexNode leftKey = null;
      RexNode rightKey = null;
      int leftInput = 0;
      int rightInput = 0;
      List<RelDataTypeField> leftFields = null;
      List<RelDataTypeField> rightFields = null;
      boolean reverse = false;

      SqlKind kind = call.getKind();

      // Only consider range operators if we haven't already seen one
      if ((kind == SqlKind.EQUALS)
          || (filterNulls != null
          && kind == SqlKind.IS_NOT_DISTINCT_FROM)
          || (rangeOp != null
          && rangeOp.isEmpty()
          && (kind == SqlKind.GREATER_THAN
          || kind == SqlKind.GREATER_THAN_OR_EQUAL
          || kind == SqlKind.LESS_THAN
          || kind == SqlKind.LESS_THAN_OR_EQUAL))) {
        final List<RexNode> operands = call.getOperands();
        RexNode op0 = operands.get(0);
        RexNode op1 = operands.get(1);

        final ImmutableBitSet projRefs0 = InputFinder.bits(op0);
        final ImmutableBitSet projRefs1 = InputFinder.bits(op1);

        final ImmutableBitSet[] inputsRange = new ImmutableBitSet[inputs.size()];
        int totalFieldCount = 0;
        for (int i = 0; i < inputs.size(); i++) {
          final int firstField = totalFieldCount + sysFieldCount;
          totalFieldCount = firstField + inputs.get(i).getRowType().getFieldCount();
          inputsRange[i] = ImmutableBitSet.range(firstField, totalFieldCount);
        }

        boolean foundBothInputs = false;
        for (int i = 0; i < inputs.size() && !foundBothInputs; i++) {
          if (projRefs0.intersects(inputsRange[i])
                  && projRefs0.union(inputsRange[i]).equals(inputsRange[i])) {
            if (leftKey == null) {
              leftKey = op0;
              leftInput = i;
              leftFields = inputs.get(leftInput).getRowType().getFieldList();
            } else {
              rightKey = op0;
              rightInput = i;
              rightFields = inputs.get(rightInput).getRowType().getFieldList();
              reverse = true;
              foundBothInputs = true;
            }
          } else if (projRefs1.intersects(inputsRange[i])
                  && projRefs1.union(inputsRange[i]).equals(inputsRange[i])) {
            if (leftKey == null) {
              leftKey = op1;
              leftInput = i;
              leftFields = inputs.get(leftInput).getRowType().getFieldList();
            } else {
              rightKey = op1;
              rightInput = i;
              rightFields = inputs.get(rightInput).getRowType().getFieldList();
              foundBothInputs = true;
            }
          }
        }

        if ((leftKey != null) && (rightKey != null)) {
          // adjustment array
          int[] adjustments = new int[totalFieldCount];
          for (int i = 0; i < inputs.size(); i++) {
            final int adjustment = inputsRange[i].nextSetBit(0);
            for (int j = adjustment; j < inputsRange[i].length(); j++) {
              adjustments[j] = -adjustment;
            }
          }

          // replace right Key input ref
          rightKey =
              rightKey.accept(
                  new RelOptUtil.RexInputConverter(
                      rexBuilder,
                      rightFields,
                      rightFields,
                      adjustments));

          // left key only needs to be adjusted if there are system
          // fields, but do it for uniformity
          leftKey =
              leftKey.accept(
                  new RelOptUtil.RexInputConverter(
                      rexBuilder,
                      leftFields,
                      leftFields,
                      adjustments));

          RelDataType leftKeyType = leftKey.getType();
          RelDataType rightKeyType = rightKey.getType();

          if (leftKeyType != rightKeyType) {
            // perform casting using Hive rules
            TypeInfo rType = TypeConverter.convert(rightKeyType);
            TypeInfo lType = TypeConverter.convert(leftKeyType);
            TypeInfo tgtType = FunctionRegistry.getCommonClassForComparison(lType, rType);

            if (tgtType == null) {
              throw new CalciteSemanticException(
                  "Cannot find common type for join keys "
                      + leftKey + " (type " + leftKeyType + ") and "
                      + rightKey + " (type " + rightKeyType + ")");
            }
            RelDataType targetKeyType = TypeConverter.convert(tgtType, rexBuilder.getTypeFactory());

            if (leftKeyType != targetKeyType && TypeInfoUtils.isConversionRequiredForComparison(tgtType, lType)) {
              leftKey =
                  rexBuilder.makeCast(targetKeyType, leftKey);
            }

            if (rightKeyType != targetKeyType && TypeInfoUtils.isConversionRequiredForComparison(tgtType, rType)) {
              rightKey =
                  rexBuilder.makeCast(targetKeyType, rightKey);
            }
          }
        }
      }

      if ((leftKey != null) && (rightKey != null)) {
        // found suitable join keys
        // add them to key list, ensuring that if there is a
        // non-equi join predicate, it appears at the end of the
        // key list; also mark the null filtering property
        addJoinKey(
            joinKeys.get(leftInput),
            leftKey,
            (rangeOp != null) && !rangeOp.isEmpty());
        addJoinKey(
            joinKeys.get(rightInput),
            rightKey,
            (rangeOp != null) && !rangeOp.isEmpty());
        if (filterNulls != null
            && kind == SqlKind.EQUALS) {
          // nulls are considered not matching for equality comparison
          // add the position of the most recently inserted key
          filterNulls.add(joinKeys.get(leftInput).size() - 1);
        }
        if (rangeOp != null
            && kind != SqlKind.EQUALS
            && kind != SqlKind.IS_DISTINCT_FROM) {
          if (reverse) {
            kind = reverse(kind);
          }
          rangeOp.add(op(kind, call.getOperator()));
        }
        return;
      } // else fall through and add this condition as nonEqui condition
    }

    // The operator is not of RexCall type
    // So we fail. Fall through.
    // Add this condition to the list of non-equi-join conditions.
    nonEquiList.add(condition);
  }
Splits out the equi-join (and optionally, a single non-equi) components
of a join condition, and returns what's left. Projection might be
required by the caller to provide join keys that are not direct field
references.

@param sysFieldList  list of system fields
@param inputs        join inputs
@param condition     join condition
@param joinKeys      The join keys from the inputs which are equi-join
                     keys
@param filterNulls   The join key positions for which null values will not
                     match. null values only match for the "is not distinct
                     from" condition.
@param rangeOp       if null, only locate equi-joins; otherwise, locate a
                     single non-equi join predicate and return its operator
                     in this list; join keys associated with the non-equi
                     join predicate are at the end of the key lists
                     returned
@return What's left, never null
@throws CalciteSemanticException
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/HiveRelOptUtil.java