content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to you under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License.  You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.calcite.sql.fun;
  
  import org.apache.calcite.sql.SqlCall;
  import org.apache.calcite.sql.SqlKind;
  import org.apache.calcite.sql.SqlOperatorBinding;
  import org.apache.calcite.sql.SqlSpecialOperator;
  import org.apache.calcite.sql.SqlWriter;
  import org.apache.calcite.sql.type.InferTypes;
  import org.apache.calcite.sql.type.IntervalSqlType;
  import org.apache.calcite.sql.type.OperandTypes;
  import org.apache.calcite.sql.type.SqlReturnTypeInference;
  import org.apache.calcite.sql.type.SqlTypeTransforms;
  import org.apache.calcite.sql.validate.SqlMonotonicity;
  
  /**
   * Operator that adds an INTERVAL to a DATETIME.
   */
  public class SqlDatetimePlusOperator extends SqlSpecialOperator {
    private static final SqlReturnTypeInference RETURN_TYPE_INFERENCE =
        opBinding ->
            SqlTimestampAddFunction.deduceType(opBinding.getTypeFactory(),
                ((IntervalSqlType) opBinding.getOperandType(1))
                    .getIntervalQualifier().getStartUnit(),
                opBinding.getOperandType(0));
  
    //~ Constructors -----------------------------------------------------------
  
    SqlDatetimePlusOperator() {
      super("+", SqlKind.PLUS, 40, true,
          RETURN_TYPE_INFERENCE.andThen(SqlTypeTransforms.TO_NULLABLE),
          InferTypes.FIRST_KNOWN, OperandTypes.MINUS_DATE_OPERATOR);
    }
  
    //~ Methods ----------------------------------------------------------------
  
    @Override public void unparse(
        SqlWriter writer,
        SqlCall call,
        int leftPrec,
        int rightPrec) {
      writer.getDialect().unparseSqlDatetimeArithmetic(
          writer, call, SqlKind.PLUS, leftPrec, rightPrec);
    }
  
    @Override public SqlMonotonicity getMonotonicity(SqlOperatorBinding call) {
      return SqlStdOperatorTable.PLUS.getMonotonicity(call);
    }
  }
  