How to use

SqlReturnTypeInference

in

org.apache.calcite.sql.type

 public RelDataType inferReturnType(SqlOperatorBinding opBinding) {
  for (SqlReturnTypeInference rule : rules) {
   RelDataType ret = rule.inferReturnType(opBinding);
   if (ret != null) {
    return ret;
   }
  }
  return null;
 }
}

 public RelDataType inferReturnType(SqlOperatorBinding opBinding) {
  for (SqlReturnTypeInference rule : rules) {
   RelDataType ret = rule.inferReturnType(opBinding);
   if (ret != null) {
    return ret;
   }
  }
  return null;
 }
}

 public RelDataType inferReturnType(
   SqlOperatorBinding opBinding) {
  RelDataType ret = rule.inferReturnType(opBinding);
  if (ret == null) {
   // inferReturnType may return null; transformType does not accept or
   // return null types
   return null;
  }
  for (SqlTypeTransform transform : transforms) {
   ret = transform.transformType(opBinding, ret);
  }
  return ret;
 }
}

 public RelDataType inferReturnType(
   SqlOperatorBinding opBinding) {
  RelDataType ret = rule.inferReturnType(opBinding);
  if (ret == null) {
   // inferReturnType may return null; transformType does not accept or
   // return null types
   return null;
  }
  for (SqlTypeTransform transform : transforms) {
   ret = transform.transformType(opBinding, ret);
  }
  return ret;
 }
}

/**
 * Infers the return type of an invocation of this operator; only called
 * after the number and types of operands have already been validated.
 * Subclasses must either override this method or supply an instance of
 * {@link SqlReturnTypeInference} to the constructor.
 *
 * @param opBinding description of invocation (not necessarily a
 * {@link SqlCall})
 * @return inferred return type
 */
public RelDataType inferReturnType(
  SqlOperatorBinding opBinding) {
 if (returnTypeInference != null) {
  return returnTypeInference.inferReturnType(opBinding);
 }
 // Derived type should have overridden this method, since it didn't
 // supply a type inference rule.
 throw Util.needToImplement(this);
}

/**
 * Infers the return type of an invocation of this operator; only called
 * after the number and types of operands have already been validated.
 * Subclasses must either override this method or supply an instance of
 * {@link SqlReturnTypeInference} to the constructor.
 *
 * @param opBinding description of invocation (not necessarily a
 * {@link SqlCall})
 * @return inferred return type
 */
public RelDataType inferReturnType(
  SqlOperatorBinding opBinding) {
 if (returnTypeInference != null) {
  RelDataType returnType = returnTypeInference.inferReturnType(opBinding);
  if (returnType == null) {
   throw new IllegalArgumentException("Cannot infer return type for "
     + opBinding.getOperator() + "; operand types: "
     + opBinding.collectOperandTypes());
  }
  return returnType;
 }
 // Derived type should have overridden this method, since it didn't
 // supply a type inference rule.
 throw Util.needToImplement(this);
}

public RelDataType inferReturnType(
  SqlOperatorBinding opBinding) {
 SqlCallBinding callBinding = (SqlCallBinding) opBinding;
 ExplicitOperatorBinding newOpBinding =
   new ExplicitOperatorBinding(
     opBinding,
     collectOperandTypes(
       callBinding.getValidator(),
       callBinding.getScope(),
       callBinding.getCall()));
 return ReturnTypes.BOOLEAN_NULLABLE.inferReturnType(
   newOpBinding);
}

public RelDataType inferReturnType(
  SqlOperatorBinding opBinding) {
 SqlCallBinding callBinding = (SqlCallBinding) opBinding;
 ExplicitOperatorBinding newOpBinding =
   new ExplicitOperatorBinding(
     opBinding,
     collectOperandTypes(
       callBinding.getValidator(),
       callBinding.getScope(),
       callBinding.getCall()));
 return ReturnTypes.BOOLEAN_NULLABLE.inferReturnType(
   newOpBinding);
}

  TypeInferenceUtils.getDrillSqlReturnTypeInference(SqlKind.SUM.name(),
    ImmutableList.of())
   .inferReturnType(oldCall.createBinding(oldAggRel));
sumType = typeFactory.createTypeWithNullability(sumType, true);
final AggregateCall sumArgSquaredAggCall =

  TypeInferenceUtils.getDrillSqlReturnTypeInference(SqlKind.SUM.name(),
    ImmutableList.of())
   .inferReturnType(oldCall.createBinding(oldAggRel));
sumType =
  typeFactory.createTypeWithNullability(