[SPARK-54588][SQL] Add time_format function to convert TIME values to formatted string representations

[vinodkc]

What changes were proposed in this pull request?

This PR adds a new time_format function that converts TIME data type values to formatted string representations, providing functionality similar to date_format but specifically designed for TIME values.

Why are the changes needed?

Users need a standard way to format TIME values as strings for:

• Display purposes: Presenting time in user-friendly formats
• Reporting: Generating formatted output for reports and dashboards
• Data export: Converting TIME values to specific string formats for external systems
• Localization: Supporting different time display conventions (12-hour vs 24-hour)

Does this PR introduce any user-facing change?

Yes, this PR adds a new public API function.

Scala API

import org.apache.spark.sql.functions._

df.select(time_format($"time_col", "HH:mm:ss"))
df.select(time_format($"time_col", "hh:mm:ss a"))

Python API

from pyspark.sql import functions as F

df.select(F.time_format("time_col", "HH:mm:ss"))
df.select(F.time_format("time_col", "hh:mm:ss a"))

SQL Usage

SELECT time_format(TIME'14:30:45', 'HH:mm:ss');           -- '14:30:45'
SELECT time_format(TIME'14:30:45.1234', 'hh-mm-ss.SS a');         -- '02-30-45.12 PM'
SELECT time_format(TIME'09:05:00', 'h:mm a');             -- '9:05 AM'

Format Pattern Support

Pattern	Description	Example Output
HH:mm:ss	24-hour format	14:30:45
hh:mm:ss a	12-hour with AM/PM	02:30:45 PM
H:mm	Single-digit hour	9:15
HH:mm:ss.SSS	With milliseconds	14:30:45.123
HH:mm:ss.SSSSSS	With microseconds	14:30:45.123456
HH-mm-ss	Custom separator	14-30-45
'Time:' HH:mm	With text literal	Time: 14:30

How was this patch tested?

Added tests in TimeExpressionsSuite, TimeFunctionsSuiteBase

Was this patch authored or co-authored using generative AI tooling?

No