nictownsend commented on code in PR #25763: URL: https://github.com/apache/flink/pull/25763#discussion_r1890537094
########## flink-table/flink-table-runtime/src/main/java/org/apache/flink/table/runtime/functions/scalar/ToTimestampLtzFunction.java: ########## @@ -0,0 +1,128 @@ +/* + * 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; + +/** + * 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 TimestampData eval(DecimalData epoch) { + if (epoch == null) { + return null; + } + + return DateTimeUtils.toTimestampData(epoch); + } + + public @Nullable TimestampData eval(StringData timestamp) { Review Comment: Possibly too much for this particular PR - but is it worth considering whether expanding the behaviour to support multiple default format? For example, using https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTimeFormatterBuilder.html to support multiple formats? E.g ISO + SQL as default matchers? I have previously used something like https://www.baeldung.com/java-parsing-dates-many-formats#using-datetimeformatterbuilder when writing UDFs around parsing time to allow for multiple formats within a data source, or to allow for more flexible SQL re-use because I don't have to remember to swap between ISO and SQL or write date formats to cover different zone indcators. ########## flink-table/flink-table-common/src/main/java/org/apache/flink/table/utils/DateTimeUtils.java: ########## @@ -421,6 +436,21 @@ public static TimestampData parseTimestampData(String dateStr, int precision, Ti .toInstant()); } + public static TimestampData parseTimestampData(String dateStr, String format, String timezone) { + if (dateStr == null || format == null || timezone == null) { + return null; + } + + TimestampData ts = parseTimestampData(dateStr, format); + if (ts == null) { + return null; + } + + ZonedDateTime utcZoned = ts.toLocalDateTime().atZone(UTC_ZONE.toZoneId()); + ZonedDateTime targetTime = utcZoned.withZoneSameInstant(ZoneId.of(timezone)); Review Comment: If I call this with `dateStr = 01-01-2000 00:00:00` and `timezone = UTC+01:00` - then I am asking to parse a zoned timestamp `01-01-2000 00:00:00 UTC+1` (which is `31-12-1999 23:00:00` in UTC). This code creates a `ZonedDateTime` of `01-01-2000 00:00:00 UTC`. It then creates a new `ZonedDateTime` with `UTC+1` using `withZoneSameInstant` - this means both objects contain the same instant - so `targetTime.toInstant()` is returning the instant of `01-01-2000 00:00:00 UTC` I think you instead need to use `withZoneSameLocal` - that converts the timestamp into the same local time but in the new timezone. ``` LocalDateTime in = LocalDateTime.of(2000,01,01,0,0); ZonedDateTime atZone = in.atZone(ZoneId.of("UTC")); ZonedDateTime otherZoneInstant = atZone.withZoneSameInstant(ZoneId.of("UTC+1")); ZonedDateTime otherZoneLocal = atZone.withZoneSameLocal(ZoneId.of("UTC+1")); System.out.println(otherZoneInstant); //2000-01-01T01:00+01:00[UTC+01:00] System.out.println(otherZoneLocal); //2000-01-01T00:00+01:00[UTC+01:00] - correct value ``` -- This is an automated message from the Apache Git Service. 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