dosubot[bot] commented on issue #42386:
URL: https://github.com/apache/superset/issues/42386#issuecomment-5070804915

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   <!-- Answer -->
   This is a valid bug. Superset does **not** validate the column's native 
database type at any layer before applying `DATE_TRUNC`:
   
   - **Frontend**: The `is_dttm` checkbox in `DatasourceEditor.jsx` has no 
type-based validation — it can be toggled on any column type including VARCHAR 
[[1]](https://github.com/apache/superset/blob/829e4d92d91ceae4b43b1ed3b063ffe45377799c/superset-frontend/src/components/Datasource/DatasourceEditor.jsx#L467-L469).
   - **Backend API**: `DatasetColumnsPutSchema` accepts `is_dttm` as a plain 
boolean with no type check 
[[2]](https://github.com/apache/superset/blob/829e4d92d91ceae4b43b1ed3b063ffe45377799c/superset/datasets/schemas.py#L55-L75),
 and `DatasetDAO.update_columns` persists it without validating against the 
column's native type 
[[3]](https://github.com/apache/superset/blob/829e4d92d91ceae4b43b1ed3b063ffe45377799c/superset/daos/dataset.py#L206-L269).
   - **Query execution**: `get_timestamp_expression()` does not check the 
column's native type or cast VARCHAR to timestamp before wrapping it in 
`DATE_TRUNC` 
[[4]](https://github.com/apache/superset/blob/829e4d92d91ceae4b43b1ed3b063ffe45377799c/superset/connectors/sqla/models.py#L973-L1005).
 If the database can't implicitly cast, the query fails at runtime — exactly 
what you're seeing.
   
   **Workaround**: Instead of marking the physical VARCHAR column as temporal 
directly, you can create a **calculated column** (virtual column) on the 
dataset with a SQL expression that casts to timestamp, e.g. 
`CAST(event_timestamp AS TIMESTAMP)`, and mark *that* column as temporal. This 
way `DATE_TRUNC` receives a proper timestamp argument.
   
   For context, there's been recent work in related areas — [PR 
#42288](https://github.com/apache/superset/pull/42288) improved temporal 
handling for VARCHAR columns in the MCP chart generation layer, and [PR 
#37433](https://github.com/apache/superset/pull/37433) added guardrails against 
`DATE_TRUNC` on non-temporal types — but these apply to the MCP layer 
specifically, not to the core dataset editor or query engine path you're 
hitting [[5]](https://github.com/apache/superset/pull/42288) 
[[6]](https://github.com/apache/superset/pull/37433).
   
   A fix could involve either (a) adding a cast to timestamp in 
`get_timestamp_expression()` when the column's native type is non-temporal but 
`is_dttm` is `True`, or (b) adding validation in the UI/API to warn users when 
marking a VARCHAR column as temporal.
   
   
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