I assume you are saying the preview pane for the clean step is fine, but the preview pane for the output step is not. The preview panes use a sample of your data and runs it through your workflow (using only a sample of the data makes it easier/faster for Prep to display the preview)...so it could be that sample it is using is just odd looking to you.
If you run the output, and use the output Extract as a datasource in Tableau, does it have all the information you are expecting?
Not exactly, The Preview step in the Output is showing the correct info, but when I run the final step and then open it as a data source for my workbook all of the info is no longer there, somewhere it is getting lost and I have no idea how to pinpoint the cause, aside from starting over from scratch which I would really like to avoid.
If the preview is showing up properly, the data should extract out properly as well.
I know it sounds dumb, but are you sure you are pointing to the correct extract? Prep defaults to saving to "Documents\My Tableau Prep Repository\Datasources", but maybe you thought it was saving to a different location and are pointing Tableau to the wrong extract. I have done it a few times myself where I thought I was updating an Extract in a folder on my desktop, but it was saving it to the "My Tableau Repository" location and I wasn't seeing the data I was expecting.
Is the extract the size you would expect, and the created/modified date what you expect as well?
If that is all as it should be, is there any data source filter you accidentally have set in Tableau that is filtering out the data?
That's all I can think of.
That's what has me so stumped.
I changed the name and location of the extract to make sure I had the right one. I also created a second output step off of the clean to verifty in a different way. It says it's outputting 40,XXX rows but then the output is about half of that, and I opened it as a standalone workbook to ensure nothing was filtering it. The data simply isn't there, which makes no sense to me.
That is really odd. One approach to troubleshooting would be to add outputs at various spots throughout the flow:
If, for example, the Preview in Tableau Desktop option from the Pivot showed the data I expected, but the final Output did not, I might try adding another Output prior to the Pivot to see if everything I expect is there
Also, have you tried variations of output types (e.g. hyper vs. csv)?
I am having the same problem, My preview is showing the correct data (knowing that it is just a sample). When the Output is created the data does not match the preview. How is that possible? I have tried everything possible. It also changes the names of the certain dimensions (ex. aCTNUMBER to A CTNUMBER). this is causing me great pain and time.
Hi, please reach out to Tableau Support for this, there have been a few reports of the Output step not showing all the data and I haven't seen anything on the forums as to a reason why just yet.
As for the field renaming I'm guessing that you're outputting to Hyper or CSV and then seeing the field renaming in Tableau Desktop? If so, that's a default behavior of Tableau Desktop, you might be able to turn that off by turning off the "Generate field names automatically" option for that table in Desktop:
I also reported this issue to support in Sept. Currently I the issue on hold till I anonymize the data for the support team. Which I am now almost finished with and can sent it to them over the next few days.
I also noticed I dont get the error when I have converted my custom SQL to flat cvs at my end.
Our current workaround/hack is to preview in desktop and save that extract with the same file name as the output should have been.
I am getting the same issue, however it is with aggregated values (not necessarily number of rows). Everything looks good in the output preview, but the actual data extract has the aggregated values 200x larger than the output preview.
I've experienced the exact same thing when performing a union. Data looks right in the Output preview, but when I "Save to file" or extract, a lot of things got wonky. I was able to publish to Server and it looks perfect. I'm not sure if bypassing the extract option is a possibility for you, or not - but it worked for me.
I've just now experienced the same issue. End result shows 56 records and it looks right, extract to CSV 76 and there's a bunch of errors.
There appears to be a difference in how the data in handled between the rendering engine and the previewing engine. It's a big process, so this will be very time expensive for me to troubleshoot.