dawidwys commented on code in PR #23612: URL: https://github.com/apache/flink/pull/23612#discussion_r1447245781
########## flink-table/flink-table-planner/src/main/java/org/apache/flink/table/planner/operations/converters/SqlShowDatabasesConverter.java: ########## @@ -0,0 +1,51 @@ +/* + * 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.flink.table.planner.operations.converters; + +import org.apache.flink.sql.parser.dql.SqlShowDatabases; +import org.apache.flink.table.catalog.CatalogManager; +import org.apache.flink.table.operations.Operation; +import org.apache.flink.table.operations.ShowDatabasesOperation; + +/** A converter for {@link SqlShowDatabases}. */ +public class SqlShowDatabasesConverter implements SqlNodeConverter<SqlShowDatabases> { + + @Override + public Operation convertSqlNode(SqlShowDatabases sqlShowDatabases, ConvertContext context) { + if (sqlShowDatabases.getPreposition() == null) { + return new ShowDatabasesOperation( + sqlShowDatabases.getLikeType(), + sqlShowDatabases.getLikeSqlPattern(), + sqlShowDatabases.isNotLike()); + } else { + CatalogManager catalogManager = context.getCatalogManager(); + String[] fullCatalogName = sqlShowDatabases.getCatalog(); + String catalogName = + fullCatalogName.length == 0 + ? catalogManager.getCurrentCatalog() + : fullCatalogName[0]; Review Comment: But, if the catalogName is null, doesn't it mean the user did not provide the name? What are the situation that `catalogName` can be null? Can it happen in any other situation than if there is no `FROM/IN catalog`? To be honest the situation that the prepostion is not null, but the catalog name is empty looks like a bug to me. Is it an equivalent to `SHOW DATABASES FROM LIKE ...`? This doesn't look like a valid SQL statement. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@flink.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
