MallikarjunaReddyN opened a new issue, #42386:
URL: https://github.com/apache/superset/issues/42386
### Bug description
When using a Physical Dataset in Apache Superset, users can mark a VARCHAR
column as Temporal from the dataset column configuration.
Superset saves this metadata successfully, but when creating a Time-series
chart using that column, Superset generates a DATE_TRUNC() expression directly
on the VARCHAR column.
For PostgreSQL databases, this results in a query execution failure because
DATE_TRUNC() does not support VARCHAR arguments.
Steps to reporduce:
1. Create a PostgreSQL table
```
CREATE TABLE website_events (
id SERIAL PRIMARY KEY,
event_name VARCHAR(50),
user_count INTEGER,
event_timestamp VARCHAR(30)
);
```
2. Insert sample data
```
INSERT INTO website_events
(event_name, user_count, event_timestamp)
VALUES
('Page View', 120, '2026-07-01 08:00:00'),
('Login', 80, '2026-07-01 09:00:00'),
('Purchase', 40, '2026-07-01 10:00:00'),
('Logout', 60, '2026-07-01 11:00:00'),
('Page View', 200, '2026-07-02 08:00:00'),
('Login', 100, '2026-07-02 09:00:00'),
('Purchase', 55, '2026-07-02 10:00:00'),
('Logout', 70, '2026-07-02 11:00:00');
```
3. Create a Physical Dataset
4. Edit dataset columns
`Dataset → Edit Dataset → Columns` Change: event_timestamp to `Is temporal =
True`
5. Create a Time-series chart
```
Time Column:
event_timestamp
Time Grain:
Day
Metric:
SUM(user_count)
```
**Actual behavior:**
Superset generates SQL similar to:
```
SELECT
DATE_TRUNC('day', event_timestamp) AS event_timestamp,
SUM(user_count) AS sum__user_count
FROM website_events
GROUP BY DATE_TRUNC('day', event_timestamp)
ORDER BY event_timestamp;
```
PostgreSQL returns:
```
psycopg2.errors.UndefinedFunction:
function date_trunc(unknown, character varying) does not exist
LINE 1:
SELECT DATE_TRUNC('day', event_timestamp)
^
HINT:
No function matches the given name and argument types.
You might need to add explicit type casts.
```
### Screenshots/recordings
https://github.com/user-attachments/assets/ffb06c99-82c8-48dc-bc4e-57c0baab6042
### Superset version
master / latest-dev
### Python version
3.11
### Node version
18 or greater
### Browser
Chrome
### Additional context
Superset backend logs:
2026-07-24 13:43:59,495:WARNING:superset.models.helpers:Query SELECT
DATE_TRUNC('day', event_timestamp) AS event_timestamp, sum(user_count) AS
"SUM(user_count)"
FROM public.website_events GROUP BY DATE_TRUNC('day', event_timestamp) ORDER
BY "SUM(user_count)" DESC
LIMIT 10000 on schema public failed
Traceback (most recent call last):
File "/home/superset/Personal/superset/superset/models/helpers.py", line
1668, in query
df = self.database.get_df(
^^^^^^^^^^^^^^^^^^^^^
File "/home/superset/Personal/superset/superset/models/core.py", line 909,
in get_df
cursor, rows, description = self._execute_sql_with_mutation_and_logging(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/superset/Personal/superset/superset/models/core.py", line 861,
in _execute_sql_with_mutation_and_logging
self.db_engine_spec.execute(cursor, sql_, self)
File "/home/superset/Personal/superset/superset/db_engine_specs/base.py",
line 2224, in execute
raise cls.get_dbapi_mapped_exception(ex) from ex
File "/home/superset/Personal/superset/superset/db_engine_specs/base.py",
line 2220, in execute
cursor.execute(query)
psycopg2.errors.UndefinedFunction: function date_trunc(unknown, character
varying) does not exist
LINE 1: SELECT DATE_TRUNC('day', event_timestamp) AS event_timestamp...
^
HINT: No function matches the given name and argument types. You might need
to add explicit type casts.
2026-07-24 13:43:59,511:INFO:werkzeug:127.0.0.1 - - [24/Jul/2026 13:43:59]
"POST /api/v1/chart/data HTTP/1.1" 400 -
### Checklist
- [x] I have searched Superset docs and Slack and didn't find a solution to
my problem.
- [x] I have searched the GitHub issue tracker and didn't find a similar bug
report.
- [x] I have checked Superset's logs for errors and if I found a relevant
Python stacktrace, I included it here as text in the "additional context"
section.
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