Signed-off-by: Yury-Fridlyand yuryf@bitquilltech.com

Description

TYPEOF function is useful for debugging to check types of other functions. Extremely useful for testing and debugging upcoming PRs with datetime functions.
Not added to documentation, because it is not supposed for an end user.
See team review discussion in Bit-Quill#123.

Usage

opensearchsql> SELECT typeof(DATETIME('1961-04-12 09:07:00')), typeof(CAST('1961-04-12 09:07:00' AS TIMESTAMP)), typeof(CAST('09:07:00' AS TIME)), typeof(CAST('1961-04-12' AS DATE));
Output longer than terminal width
Do you want to display data vertically for better visual effect? [y/N]: y
fetched rows / total rows = 1/1
-[ RECORD 1 ]-------------------------
typeof(DATETIME('1961-04-12 09:07:00')           | DATETIME
typeof(CAST('1961-04-12 09:07:00' AS TIMESTAMP)) | TIMESTAMP
typeof(CAST('09:07:00' AS TIME))                 | TIME
typeof(CAST('1961-04-12' AS DATE))               | DATE

UPD

TYPEOF function perfectly works with SQL types. It works with some OpenSearch (OpenSearchDataType) types, which could be implicitly casted to SQL ones. Unfortunately, function can't accept OpenSearch types, so some information lost.
IP, GEO_POINT, BINARY and NESTED types cause crash.
https://github.com/Bit-Quill/opensearch-project-sql/blob/d02e16f147a9f3e6afa065f701efa7ece70d310b/opensearch/src/main/java/org/opensearch/sql/opensearch/data/type/OpenSearchDataType.java#L49-L53

Check List

• New functionality includes testing.
  • All tests pass, including unit test, integration test and doctest
• New functionality has been documented.
  • New functionality has javadoc added
  • New functionality has user manual doc added
• Commits are signed per the DCO using --signoff

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