<p dir="auto">Hi,</p>
<p dir="auto">I wonder whether Superset offers a stepped line chart (I have been googled for quite some times but couldn't find any).</p>
<p dir="auto">It is like something like <a href="https://www.chartjs.org/samples/latest/charts/line/stepped.html" rel="nofollow">this</a>.</p>
<p dir="auto">Useful cases:</p>
<ul dir="auto">
<li>Showing the bid and the ask price of stock price over time in 1 single chart.</li>
<li>Showing multiple time series in one chart.</li>
</ul>
<p dir="auto">Currently, I have a database schema like this:<br>
symbol varhcar(16);<br>
is_bid boolean;<br>
price double;<br>
time timestamp(6);</p>
<p dir="auto">And then I use "time series - line chart" as the visualization type, "sum(price)" as metrics, and group by "symbol" and "is_bid".</p>
<p dir="auto">Then the chart will have many broken lines because not every timestamp for each set of symbol and is_bid exists for another set of symbol and is_bid.  Concrete example:<br>
DB row 1: symbol = AAPL, time = 9:00:00AM, is_bid = TRUE, price = 140.00<br>
DB row 2: symbol = AAPL, time = 9:00:01AM, is_bid = FALSE, price = 140.05<br>
DB row 3: symbol = AAPL, time = 9:00:03AM, is_bid = TRUE, price = 140.01<br>
DB row 4: symbol = AAPL, time = 9:00:05AM, is_bid = FALSE, price = 140.06</p>
<p dir="auto">Then the line for AAPL's bid price will be broken between 9:00:00 and 9:00:03 because there is no entry in the DB for time = 9:00:01AM.</p>
<p dir="auto">One solution is to have a script to get all the unique timestamps, and then populate additional rows per symbol per is_bid based on the previous value of the corresponding set of symbol and is_bid (as "step before interpolation" makes sense in this case), creating a giant table and additional work for all stepped line charts.</p>
<p dir="auto">Hence, it would be great that superset supports (or already supported) step line chart.</p>
<p dir="auto">Thanks.</p>
<p dir="auto">Column selection is not saved in export file, and saving dataset id in export file doesn't seem to be a correct approach</p>
<h3 dir="auto">Expected results</h3>
<p dir="auto">Import a dashboard with native filter to a new workspace should work seemlessly.</p>
<h3 dir="auto">Actual results</h3>
<ol dir="auto">
<li>Selected column is not present in the export file, resulting in new dashboard native filter error with missing column selection.</li>
<li>Saving dataset id in the export file is an incorrect approach. The dataset id in a different workspace is different. In my example, dataset id =29 is already taken in the new workspace, this result in the imported dashboard showing the wrong dataset selection in native filter.</li>
</ol>
<h4 dir="auto">Screenshots</h4>
<p dir="auto"><a target="_blank" rel="noopener noreferrer nofollow" href="https://user-images.githubusercontent.com/52086618/124030259-e1268d80-d9aa-11eb-9497-f373eb670a65.png"><img src="https://user-images.githubusercontent.com/52086618/124030259-e1268d80-d9aa-11eb-9497-f373eb670a65.png" alt="image" style="max-width: 100%;"></a><br>
<a target="_blank" rel="noopener noreferrer nofollow" href="https://user-images.githubusercontent.com/52086618/124030653-411d3400-d9ab-11eb-954f-382602aee88c.png"><img src="https://user-images.githubusercontent.com/52086618/124030653-411d3400-d9ab-11eb-954f-382602aee88c.png" alt="Clipboard 2021-30-06 at 1 44 38 PM" style="max-width: 100%;"></a></p>
<h4 dir="auto">How to reproduce the bug</h4>
<ol dir="auto">
<li>Create a dashboard</li>
<li>Create a value native filter and select dataset and column</li>
<li>Export this dashboard</li>
<li>Import this dashboard to a new workspace</li>
</ol>