Tableau Desktop

Tableau Desktop is believed to be compatible with LDP.

Connecting

• Start Tableau Desktop
• From Connect… To a Server… More… select PostgreSQL
• Input connection details

Executing Custom SQL

• Select “New Custom SQL” from sidebar
• Paste in single SQL statement, but do not include trailing “;”

Note: It is possible to join custom SQL to other existing tables in the database, which might be necessary if you can’t accomplish everything in a single SQL statement

See also: Tableau documentation on custom SQL

Building Queries

Tableau gives direct access to database tables, so tables can be joined ad hoc.

• Drag tables one by one into data source canvas, but note that order matters: Tableau tries to determine joins automatically by table contents, hard to fix later
• Can adjust whether Tableau uses left/right/inner/outer join by clicking on the Venn diagram between the tables

Viewing and Saving Results

Basic Data Export to CSV

Immediately after executing the query, a user can use the Data menu to export results to a .csv file, which could then be opened in Excel or another data analysis program.

Formatting note: Tableau adds a “Number of Records” column automatically and may reorder other columns alphabetically, so the exported CSV may not match the Tableau table.

Export Worksheet

If you create a visualization based on the data from the query, Tableau Desktop will also allow you to export that visualization (either in a worksheet or in a dashboard) as an image (.png, .bmp, or .jpg format). You can also print worksheets and dashboards to PDF. You can also export just the data used in a particular worksheet from the Worksheet menu.

Custom Reports from Results

Tableau is designed to create visualizations, including both tables and charts/graphs. Tableau can easily add totals and subtotals, filter out certain groups or date ranges, create custom groups, change the names of variables and data points, etc. It may be possible or even advisable to generate custom visuals in Tableau rather than using a SQL query to perform aggregations and add formatting. You can either join the tables directly in Tableau or use custom SQL to join tables and select specific columns.