add DropTableStatement

/*

 * Copyright 2016-2018 shardingsphere.io.

 * <p>

 * Licensed 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.

 * </p>

 */

package io.shardingsphere.core.parsing.antlr.sql.statement.ddl;

import lombok.Getter;

/**

 * Drop table statement.

 *

 * @author zhangliang

 */

@Getter

public final class DropTableStatement extends DDLStatement {

}

                        extractor-rule-refs="tableNames, indexNames, columnDefinitions, outlinePrimaryKey" />

    <sql-statement-rule context="alterTable" sql-statement-class="io.shardingsphere.core.parsing.antlr.sql.statement.ddl.AlterTableStatement" 

                        extractor-rule-refs="tableNames, indexNames, addColumnDefinition, modifyColumnDefinition, changeColumnDefinition, dropColumnDefinition, outlinePrimaryKey, dropPrimaryKey, renameTable" />

    <sql-statement-rule context="dropTable" sql-statement-class="io.shardingsphere.core.parsing.antlr.sql.statement.ddl.DDLStatement" extractor-rule-refs="tableNames" />

    <sql-statement-rule context="dropTable" sql-statement-class="io.shardingsphere.core.parsing.antlr.sql.statement.ddl.DropTableStatement" extractor-rule-refs="tableNames" />

    <sql-statement-rule context="truncateTable" sql-statement-class="io.shardingsphere.core.parsing.antlr.sql.statement.ddl.DDLStatement" extractor-rule-refs="tableName" />

    <sql-statement-rule context="createIndex" sql-statement-class="io.shardingsphere.core.parsing.antlr.sql.statement.ddl.DDLStatement" extractor-rule-refs="tableName, indexName" />

    <sql-statement-rule context="dropIndex" sql-statement-class="io.shardingsphere.core.parsing.antlr.sql.statement.ddl.DDLStatement" extractor-rule-refs="tableName, indexName" />

    <sql-statement-rule context="select" sql-statement-class="io.shardingsphere.core.parsing.parser.sql.dql.select.SelectStatement" 

                        extractor-rule-refs="tableNames, indexNames, selectClause, fromWhere, groupBy, orderBy, limit" 

                        optimizer-class="dql.dialect.mysql.MySQLSelectOptimizer" />