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.dialect;
  
  import org.apache.calcite.sql.SqlDialect;
  import org.apache.calcite.sql.SqlNode;
  import org.apache.calcite.sql.SqlWriter;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * A <code>SqlDialect</code> implementation for the Sybase database.
   */
  public class SybaseSqlDialect extends SqlDialect {
    public static final SqlDialect.Context DEFAULT_CONTEXT = SqlDialect.EMPTY_CONTEXT
        .withDatabaseProduct(SqlDialect.DatabaseProduct.SYBASE);
  
    public static final SqlDialect DEFAULT = new SybaseSqlDialect(DEFAULT_CONTEXT);
  
    /** Creates a SybaseSqlDialect. */
    public SybaseSqlDialect(Context context) {
      super(context);
    }
  
    @Override public void unparseOffsetFetch(SqlWriter writer, @Nullable SqlNode offset,
        @Nullable SqlNode fetch) {
      // No-op; see unparseTopN.
      // Sybase uses "SELECT TOP (n)" rather than "FETCH NEXT n ROWS".
    }
  
    @Override public void unparseTopN(SqlWriter writer, @Nullable SqlNode offset,
        @Nullable SqlNode fetch) {
      // Parentheses are not required, but we use them to be consistent with
      // Microsoft SQL Server, which recommends them but does not require them.
      writer.keyword("TOP");
      writer.keyword("(");
      requireNonNull(fetch, "fetch");
      fetch.unparse(writer, -1, -1);
      writer.keyword(")");
      if (offset != null) {
        writer.keyword("START");
        writer.keyword("AT");
        offset.unparse(writer, -1, -1);
      }
    }
  }
  