yiyutian1 commented on code in PR #25763: URL: https://github.com/apache/flink/pull/25763#discussion_r1894166214
########## flink-table/flink-table-runtime/src/main/java/org/apache/flink/table/runtime/functions/scalar/ToTimestampLtzFunction.java: ########## @@ -0,0 +1,139 @@ +/* + * 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.runtime.functions.scalar; + +import org.apache.flink.annotation.Internal; +import org.apache.flink.table.data.DecimalData; +import org.apache.flink.table.data.StringData; +import org.apache.flink.table.data.TimestampData; +import org.apache.flink.table.functions.BuiltInFunctionDefinitions; +import org.apache.flink.table.functions.SpecializedFunction; +import org.apache.flink.table.utils.DateTimeUtils; + +import javax.annotation.Nullable; + +import java.time.DateTimeException; +import java.time.ZoneId; +import java.time.ZonedDateTime; + +import static org.apache.flink.table.utils.DateTimeUtils.parseTimestampData; + +/** + * Implementation of {@link BuiltInFunctionDefinitions#TO_TIMESTAMP_LTZ}. + * + * <p>A function that converts various time formats to TIMESTAMP_LTZ type. + * + * <p>Supported function signatures: + * + * <ul> + * <li>{@code TO_TIMESTAMP_LTZ(numeric)} -> TIMESTAMP_LTZ(3) <br> + * Converts numeric epoch time in milliseconds to timestamp with local timezone + * <li>{@code TO_TIMESTAMP_LTZ(numeric, precision)} -> TIMESTAMP_LTZ(precision) <br> + * Converts numeric epoch time to timestamp with specified precision (0 as seconds, 3 as + * milliseconds) + * <li>{@code TO_TIMESTAMP_LTZ(timestamp)} -> TIMESTAMP_LTZ(3) <br> + * Parses string timestamp using default format 'yyyy-MM-dd HH:mm:ss' + * <li>{@code TO_TIMESTAMP_LTZ(timestamp, format)} -> TIMESTAMP_LTZ(3) <br> + * Parses string timestamp using input string of format + * <li>{@code TO_TIMESTAMP_LTZ(timestamp, format, timezone)} -> TIMESTAMP_LTZ(3) <br> + * Parses string timestamp using input strings of format and timezone + * </ul> + * + * <p>Example: + * + * <pre>{@code + * TO_TIMESTAMP_LTZ('2023-01-01 10:00:00') // Parses string using default format + * TO_TIMESTAMP_LTZ(1234567890123) // Converts epoch milliseconds + * TO_TIMESTAMP_LTZ(1234567890, 0) // Converts epoch seconds + * TO_TIMESTAMP_LTZ(1234567890123, 3) // Converts epoch milliseconds + * TO_TIMESTAMP_LTZ('2023-01-01 10:00:00') // Parses string using default format + * TO_TIMESTAMP_LTZ('2023-01-01T10:00:00', 'yyyy-MM-dd\'T\'HH:mm:ss') // Parses string using input format + * TO_TIMESTAMP_LTZ('2023-01-01 10:00:00', 'yyyy-MM-dd HH:mm:ss', 'UTC') // Parses string using input format and timezone + * }</pre> + */ +@Internal +public class ToTimestampLtzFunction extends BuiltInScalarFunction { + + private static final int DEFAULT_PRECISION = 3; + + public ToTimestampLtzFunction(SpecializedFunction.SpecializedContext context) { + super(BuiltInFunctionDefinitions.TO_TIMESTAMP_LTZ, context); + } + + public @Nullable TimestampData eval(Number epoch, Integer precision) { + if (epoch == null || precision == null) { + return null; + } + if (epoch instanceof Float || epoch instanceof Double) { + return DateTimeUtils.toTimestampData(epoch.doubleValue(), precision); + } + return DateTimeUtils.toTimestampData(epoch.longValue(), precision); + } + + public @Nullable TimestampData eval(DecimalData epoch, Integer precision) { + if (epoch == null || precision == null) { + return null; + } + + return DateTimeUtils.toTimestampData(epoch, precision); + } + + public @Nullable TimestampData eval(Number epoch) { + return eval(epoch, DEFAULT_PRECISION); + } + + public @Nullable TimestampData eval(DecimalData epoch) { + return eval(epoch, DEFAULT_PRECISION); + } + + public @Nullable TimestampData eval(StringData timestamp) { + if (timestamp == null) { + return null; + } + + return parseTimestampData(timestamp.toString()); + } + + public @Nullable TimestampData eval(StringData timestamp, StringData format) { + if (timestamp == null || format == null) { + return null; + } + + return parseTimestampData(timestamp.toString(), format.toString()); + } + + public @Nullable TimestampData eval( + StringData dateStr, StringData format, StringData timezone) { + if (dateStr == null || format == null || timezone == null) { + return null; + } + + TimestampData ts = parseTimestampData(dateStr.toString(), format.toString()); + if (ts == null) { + return null; + } + + try { + ZonedDateTime zoneDate = ts.toLocalDateTime().atZone(ZoneId.of(timezone.toString())); + return TimestampData.fromInstant(zoneDate.toInstant()); + } catch (DateTimeException e) { + return null; Review Comment: Good question, @davidradl and @hanyuzheng7 ! I explained the reasoning here: https://github.com/apache/flink/pull/25763#discussion_r1893222879 We return null here because it's the desired behavior. Also because it's consistent to how we handle exceptions in other DateTime methods, eg. [here](https://github.com/apache/flink/blob/7fa4f78e43bfd99a7e7a3d655a9a3641e4d7bc59/flink-table/flink-table-common/src/main/java/org/apache/flink/table/utils/DateTimeUtils.java#L447). Logging would be nice, but that also requires adding logs to other DateTime functions to make it consistent, maybe in a separate effort. Let me know if this answered your question. Thanks for the effort in reviewing this PR! I learned a lot in having these conversations. -- 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. 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