Editing Join Details

This article demonstrates how to change the specifications of existing table joins.

The following steps demonstrate how to edit the expression that defines the join to the state_abbreviations table.

  1. Navigate to the Data Model page of the dataset.

  2. Click Edit Data Model to edit the data model.

    Clicking 'Editing Data Model'
    Editing Data Model
  3. Click the (link) icon beside the state_abbreviations connection.

    Clicking the join to edit
    Clicking the Join to Edit its Definition
  4. The Join Details modal window appears.

  5. Click Edit Join.

    Clicking to edit the join
    Editing Join Detail
  6. In the Edit Join modal window, the following options are available:

    1. [Optional] Click Clear Fields to clear all already defined joins between the two tables.
    2. [Optional] Click sample data to preview the data. Click again to hide sample data.
    3. [Optional] Click Add Join Pair to add another column connection between the same two tables.
    4. [Optional] Click Add Join Expression to add a join between the two tables based on a custom SQL expression.
    5. [Optional] Click icon (minus) to remove an existing join pair or an existing join expression.
    6. [Optional] Under Join Expressions, click the text box to open the Join Expression interface. There, specify or update a custom SQL expression that defines the join conditions.
    7. Click Apply to save the changes.
    Viewing options in the 'Edit Join' Interface
    Edit Join Interface
  7. Now, let's add a join expression, and replace the original field:field join. In the Edit Join modal window do the following:

    • Remove the initial join between the two columns by clicking the (minus) icon.
    • Under Join Expressions, click the text box to open the Join Expression interface. Here you can specify or update the custom SQL expression that defines the join conditions.
    Deleting the initial join and clicking the Join Expressions box
    Click the Join Expressions box
  8. In the Join Expression modal window, do the following:

    • Enter the following expression to show only flights that have significant arrival delay, more than five minutes:
      [deststate]=[abbreviation] AND [arrdelay] > 5
    • Click Apply to save the expression and return to the Edit Join modal window.
    Entering an expression in the Join Expression modal window
    Enter a Join Expression
  9. In the Edit Join modal window, do the following:

    • Verify that the initial join between the two columns is deleted and the new join expression appears under Join Expressions.
    • Click Apply.

    Displaying the new join expression in the 'Edit Join' modal window
    Delete the Initial Join and display the New Join Expression
  10. The Data Model interface appears. You may click Show Data to display the updated table.

  11. [Optional] To revert this change prior to saving, click Undo.

  12. Click Save.