Now, if your data source is a relational database such as Oracle, SQL Server, MySQL, or Snowflake that supports a Custom SQL Input step, then you could write your own SQL to perform UNION, INTERSECT or MINUS / EXCEPT unions in Tableau Prep.īut what if you are using a data source that doesn’t support the logic? Or you need to implement it somewhere in the flow other than the input?ĭon’t worry! Tableau Prep has you covered! It has all the foundational tools to allow you to implement all kinds of data shaping logic! UNION in Tableau Prep That is, if a record exists in both tables or only in the second, it is not retained in the resulting set. MINUS unions (sometimes also called EXCEPT) keep records that are only present in the first table.INTERSECT unions return records that exist in both tables.That is, if records in the resulting set are exactly identical, only one copy is kept. UNION keeps only one copy of each unique record.However, many databases support logic beyond this kind of union: That is, all records from all tables will be included in the results. In Tableau Prep, both the Union Step itself and also the Input Step using a wildcard union are going to function as a UNION ALL. One thing I didn’t cover, but has subsequently come up is the question “What about INTERSECT and MINUS or EXCEPT Unions”? Can we achieve these types of unions in Tableau Prep? Can we do anything other than a UNION ALL? Yes! Yes, we can! Unions in Tableau Prep After reviewing the mismatched fields, users can drag and drop the fields to merge them together and fix the result of the UNION.Recently I gave a “State of the Unions” address for Tableau’s Think Data Thursday (the recording is here) in which I discussed new features for unions in Tableau Prep and Tableau Desktop. We started calling it "The Hat", as it showed up like a hat above each field. Through iteration, we put the color coded input to the top of the field so that users can understand what's going on right where it happens. We started out with the color-coded inputs to represent the input. To help users to achieve the main task of matching fields, users first need to see which fields have missing inputs. How can we offer this feature so that users perform their task right where it happens? Along the way, we kept on asking this question to test the design against the product principles. ProcessĪfter drilling down into the single most important user task, we went through design iterations to decide scope and UX flow. That is Users need to align fields that have the same meaning but different names between tables when they merge. I came in at that stage, and worked with the team to distill the problem space into the most important one. That resulted in highly complex UI that was very difficult to follow. When we first started out working on UNION feature, there were many user tasks that we assumed users need to do. When you have a lot of data with a lot of columns, it can easily become overwhelming. You, the human, would have to tell the machine that they are the same thing, so that they can be merged into the single column. ![]() in one sheet, a column name is cost, and then later, price, both intending to be the same thing. ![]() It becomes sometimes tedious task, when you have the column header in different names, e.g. This operation of merge is called "UNION" in the database world. ![]() You want to analyze the annual average spending or monthly spending trend, then you will want to merge the sheet into the single large table so that you can dice and slice the data for your purpose. Each sheet in the file contains income and spending each month. Let's say you maintain household income and spending in a spreadsheet.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |