Add support for TRY_CAST()

[lukaseder]

Numerous SQL dialects have some way of expressing TRY_CAST()

• BigQuery: SAFE_CAST: https://cloud.google.com/bigquery/docs/reference/standard-sql/functions-and-operators#safe_casting
• DuckDB: https://duckdb.org/docs/sql/expressions/cast.html
• Oracle: https://docs.oracle.com/en/database/oracle/oracle-database/19/sqlrf/VALIDATE_CONVERSION.html#GUID-DC485EEB-CB6D-42EF-97AA-4487884CB2CD
  • But there's also 12c's CAST(x AS y DEFAULT NULL ON CONVERSION ERROR)
• SQL Server: https://learn.microsoft.com/en-us/sql/t-sql/functions/try-cast-transact-sql?view=sql-server-ver16
• Snowflake: https://docs.snowflake.com/en/sql-reference/functions/try_cast
• Trino: https://trino.io/docs/current/functions/conversion.html

Tasks

• Support the above dialects
• Parser support

[lukaseder]

In some RDBMS it might be possible to emulate some pairs of data type conversions like this, e.g. from VARCHAR to INT:

CASE WHEN vc LIKE_REGEXP '-?[0-9]+' THEN CAST(vc AS INT) END

I might do this in a future release:

• Emulate TRY_CAST using regular expression checks #15545