In Tableau the default number of table discrete (blue pills) columns in a table is six. Any more than this and the left hand columns start to merge into one column. Thanks to a below comment from Joe Mako I learnt the default six can increase to 16. To increase use the Tableau menu. Analysis—Table Layout—Advanced—Rows: Maximum Levels… and change 6 to 16. However this allows you to add 17 dimensions to your table.
Continuous measures (green pills) do not have this constraint. To include multiple measures in a table use 1 pill, Measure Names. There is another article explaining how to add multiple measures to a table.
The Placeholder technique is another way to add many items to a table, and also conditional formatting. However this also comes with constraints, which are described in the article.
Use the Text Shelf to add an extra dimension to your table
Tableau is not really designed for showing tabular data but sometimes it’s useful to show line item data as part of a drill down in a table Another example, maybe you’re creating a report specifically with the purpose to export to Excel.
Note, if creating something with the sole aim of exporting to Excel, with no thought around how it appears on screen in Tableau, place all of the fields for export on the Detail shelf. They won’t appear in the Tableau dashboard BUT they will appear in the data export.
In Tableau if putting dimensions as columns in a table you are limited to 16 discrete pills before they start to merge. There is a little trick available to put one more column, the 17th column, into the table.
1. Drag the pill into the Text shelf. In this example I’ve used a Dimension called ‘Ship Mode’
2. Drag the ‘Measure Names’ pill from the Dimension section into the Columns Shelf. In the column headings you’ll notice this column now has the heading No Measure Values.
3. Click the arrow on the Measure Names pill and select Edit Aliases
4. Find the Member ‘No Measure Value’ and set the Value (Alias) to be the name you want for that Dimension
5. That’s it, you now have 17 dimension columns in your table!