Probably. Got a sample packaged workbook?
Does anyone have an idea on how to solve this?
Hi Jonny - how do you determine if an event is active? e.g., those that haven't ended yet?
Yes, the start time + duration gives the end time. For each time unit, I would like to know how many events are active at that time (i.e., overlap with that timestamp).
This is a somewhat complicated problem to solve in Tableau and there are a variety of different techniques. See Utilization, Queues, Census, Throughput for Blocks, Floors, Units, Rooms, Offices, etc. - What do you do? for some different examples and a new post by Keith Helfrich on the topic at http://redheadedstepdata.io/lookup-vs-transactional/ that describes more of the pattern of what is going on (and why it's harder to deal with in Tableau).
Thanks for the links!
I found out that in Tableau 9 on Mac, its not possible to do complex queries on csv files. So I quickly created a MySQL database and ran the query, resembling the one in Re: Headcount, when given the Arrival & Departure Dates:
FROM data d, times t
WHERE t.time >= d.start AND t.time <= d.start+d.elapsed
The dummy table times has all possible timestamps in it.
This created the tuples necessary to created the visualisation.
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I use Tableau on Mac as well and have been frustrated by the lack of custom SQL for text files.
FYI, if you can edit your data sources to add columns it is possible to do this without needing a separate DB:
1. Add a column with a value of 1 for every row to each data source.
2. In Tableau do an inner join between the two tables on that column. This nets the cross product of the two tables.
3. Create a calculated field in Tableau with a formula something like t.time >= d.start and t.time <= d.start+d.elapsed. This will return a boolean dimension.
4. Use the calculated field from step 3 as a data source filter, filtering for True. Data source filters are added to the WHERE clause of every query so it gets the same effect.
This still requires the dummy table, correct?
By dummy table you mean a time table? Yes, it does
On Tue, Aug 11, 2015 at 7:03 AM, Jonny Daenen <