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https://issues.apache.org/jira/browse/SPARK-57526?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Max Gekk resolved SPARK-57526.
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Fix Version/s: 4.3.0
Resolution: Fixed
Issue resolved by pull request 56616
[https://github.com/apache/spark/pull/56616]
> Add the `timestamp_nanos` function to create nanosecond-precision timestamps
> from numeric nanoseconds
> -----------------------------------------------------------------------------------------------------
>
> Key: SPARK-57526
> URL: https://issues.apache.org/jira/browse/SPARK-57526
> Project: Spark
> Issue Type: Sub-task
> Components: SQL
> Affects Versions: 4.3.0
> Reporter: Max Gekk
> Assignee: Max Gekk
> Priority: Major
> Labels: pull-request-available
> Fix For: 4.3.0
>
>
> h3. Background
> Part of the SPARK-56822 umbrella (nanosecond-precision timestamps). Spark
> already has
> {{timestamp_seconds}}, {{timestamp_millis}} and {{timestamp_micros}}, which
> build a
> {{TIMESTAMP}} (LTZ, microsecond precision) from a numeric count since the
> Unix epoch.
> There is no counterpart that produces a nanosecond-precision value.
> h3. Proposal
> Add a new built-in function {{timestamp_nanos(expr)}} that interprets
> {{expr}} as the
> number of nanoseconds since {{1970-01-01 00:00:00 UTC}} and returns a
> {{TIMESTAMP_LTZ(9)}}
> ({{TimestampLTZNanosType(9)}}).
> * Input: integral numeric ({{BIGINT}}).
> * Output type: {{TIMESTAMP_LTZ(9)}}.
> * Mapping to the internal pair: {{epochMicros = Math.floorDiv(n, 1000)}},
> {{nanosWithinMicro = Math.floorMod(n, 1000)}}, built via
> {{TimestampNanosVal.fromParts(epochMicros, nanosWithinMicro)}}.
> {code:sql}
> SELECT timestamp_nanos(1230219000123456789);
> -- 2008-12-25 15:30:00.123456789
> {code}
> h3. Implementation notes
> * Mirror the existing {{SecondsToTimestamp}} / {{MicrosToTimestamp}}
> expressions in
> {{datetimeExpressions.scala}}.
> * Reuse {{TimestampNanosVal.fromParts}} and {{NANOS_PER_MICROS}} from
> {{DateTimeUtils}}.
> * Register in {{FunctionRegistry}} and add to the SQL function docs/examples.
> * Provide both interpreted and codegen paths.
> h3. Acceptance criteria
> * {{timestamp_nanos}} available in SQL, Scala, Python and R function APIs.
> * Returns {{TIMESTAMP_LTZ(9)}}; sub-microsecond digits preserved.
> * Null-safe; handles negative (pre-epoch) inputs via floor semantics.
> * Unit tests + golden files (result, type, codegen) added.
> h3. Out of scope
> * The inverse {{unix_nanos}} function (separate sub-task).
> Parent: SPARK-56822
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