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- [ ] I have checked the superset logs for python stacktraces and included it here as text if any - [ ] I have reproduced the issue with at least the latest released version of superset - [ ] I have checked the issue tracker for the same issue and I haven't found one similar ### Superset version 0.26.3 ### Expected results Time Series - Line Chart rendered. ### Actual results Error with no clear message. ### Steps to reproduce 1. Create a query in SQL Lab with a datetime column and an integer column (or just use any datasource that has a datetime column and group by that column to count the number of rows) 2. Click on 'Explore' to visualize the resulting table  3. Choose Time Series - Line Chart as an option to visualize 4. Add your integer column as value for the 'Metrics' option 5. Click on 'Run Query'  Here is the trackeback I get `Traceback (most recent call last): File "/home/work/incubator-superset/superset/views/core.py", line 1115, in generate_json payload = viz_obj.get_payload() File "/home/work/incubator-superset/superset/viz.py", line 347, in get_payload payload['data'] = self.get_data(df) File "/home/work/incubator-superset/superset/viz.py", line 1217, in get_data df = self.process_data(df) File "/home/work/incubator-superset/superset/viz.py", line 1137, in process_data values=utils.get_metric_names(fd.get('metrics'))) File "/usr/local/lib/python3.6/site-packages/pandas/core/frame.py", line 5303, in pivot_table margins_name=margins_name) File "/usr/local/lib/python3.6/site-packages/pandas/core/reshape/pivot.py", line 61, in pivot_table raise KeyError(i) KeyError: 'SUM(total_visits)'` The traceback doesn't seem to be helpful. This is the query that is generated automatically to visualize the resulting table: `SELECT weekly AS __timestamp, SUM(total_visits) AS "SUM(total_visits)" FROM (SELECT DATE_TRUNC('WEEK', "timestamp") weekly, COUNT(*) total_visits FROM my_table WHERE "timestamp" >= '2018-06-01' GROUP BY 1) AS expr_qry WHERE weekly >= '1918-08-22 00:00:00' GROUP BY weekly ORDER BY "SUM(total_visits)" DESC LIMIT 50000;` I've tried the following to see if it works: - grouping the data by the column 'weekly' in the 'Query' options, - adding a value for Time Grain, - trying to visualize using both Chrome and Mozilla Firefox, - using a different time column in the table to see if there was any conflict caused by the name of the column being 'timestamp' - changing the 'Metrics' definition from 'SUM(total_visits)' to 'total_visits' -> This produces another message:   [ Full content available at: https://github.com/apache/incubator-superset/issues/5700 ] This message was relayed via gitbox.apache.org for [email protected]
