GitHub user dosubot[bot] added a comment to the discussion: Superset is not able to recognise the NULL datatype of any column
<!-- Answer --> Superset 2.1.0 and 3.0.0 both rely on the database connector and engine spec to infer column types. If the database reports a NULL or missing type for a column, Superset marks it as UNKNOWN and normally disables time-based features for that column. There is no special logic in 2.1.0 to treat NULL types as temporal—recognition depends on the type string and engine spec mapping. The fact that your 2.1.0 instance works with a NULL timestamp column is likely due to differences in the metadata returned by the database or connector, or possibly looser validation in dependencies like SQLAlchemy at that time. In 3.0.0, stricter validation or changes in dependencies mean that ambiguous or NULL types are no longer tolerated, so the column is marked as UNKNOWN and can't be used for time filters or charts. The core logic for type inference hasn't changed between these versions; the difference is likely environmental or due to dependency updates, not a deliberate change in Superset itself. [Reference: Superset 2.1.0 column type inference and engine spec logic](https://github.com/apache/superset/blob/829e4d92d91ceae4b43b1ed3b063ffe45377799c/superset/connectors/sqla/utils.py) <!-- Dosu Comment Footer --> *To reply, just mention [@dosu](https://go.dosu.dev/dosubot).* --- <sup>How did I do? [Good](https://app.dosu.dev/response-feedback/ada30563-213a-4ed8-9bab-097c4d070b4d?feedback_type=great_response) | [Irrelevant](https://app.dosu.dev/response-feedback/ada30563-213a-4ed8-9bab-097c4d070b4d?feedback_type=irrelevant_answer) | [Incorrect](https://app.dosu.dev/response-feedback/ada30563-213a-4ed8-9bab-097c4d070b4d?feedback_type=incorrect_sources) | [Verbose](https://app.dosu.dev/response-feedback/ada30563-213a-4ed8-9bab-097c4d070b4d?feedback_type=too_verbose) | [Hallucination](https://app.dosu.dev/response-feedback/ada30563-213a-4ed8-9bab-097c4d070b4d?feedback_type=hallucination) | [Report 🐛](https://app.dosu.dev/response-feedback/ada30563-213a-4ed8-9bab-097c4d070b4d?feedback_type=bug_report) | [Other](https://app.dosu.dev/response-feedback/ada30563-213a-4ed8-9bab-097c4d070b4d?feedback_type=other)</sup> [](https://app.dosu.dev/a28d3c7e-a9d3-459e-9fb6-3a6f9ff4f357/ask?utm_source=github)& nbsp;[](https://go.dosu.dev/discord-bot) [](https://twitter.com/intent/tweet?text=%40dosu_ai%20helped%20me%20solve%20this%20issue!&url=https%3A//github.com/apache/superset/discussions/35188) GitHub link: https://github.com/apache/superset/discussions/35188#discussioncomment-14444036 ---- This is an automatically sent email for notifications@superset.apache.org. To unsubscribe, please send an email to: notifications-unsubscr...@superset.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: notifications-unsubscr...@superset.apache.org For additional commands, e-mail: notifications-h...@superset.apache.org
