Editing join details

Learn how you edit an existing join to change its matching columns or define custom SQL join conditions in Cloudera Data Visualization.

Navigate to the Data Model page of the dataset.
Click Edit in the top-right corner of the page.
Click the two overlapping circles on the line connecting the tables to edit the join conditions.
Click EDIT JOIN.
The Edit Join modal is displayed.
Update the join conditions using the following options.
1. CLEAR FIELDS allows you to clear all already defined joins between the two tables.
2. Use the column drop-downs to change the matching columns.
3. allows you to edit the name of the joined table.
  important
  This action is only available when a join is created to the same table. In these cases, the table name is duplicated with a number appended to distinguish it. This alias is applied to both dimension and measure names within the joined dataset.
  If you wish to modify this duplicated alias for clarity or consistency, you can edit the duplicated table name. When you provide a new alias, it is applied to the corresponding dimension and measure names of the dataset.
4. sample data allows you to preview the data from the tables. Click it again to hide the sample data.
5. allows you to remove an existing join pair or an existing join expression.
6. Clicking the Join Expressions text box opens the Join Expression modal where you can specify or update a custom SQL expression that defines the join conditions.
7. Add Join Pair can be used to add another pair of matching columns.
8. Add Join Expression can be used to add a custom SQL condition and then define it in the SQL expression editor.
Click Apply to save the changes.
To add a a join expression and replace the original field:field join, perform the following steps in the Edit Join modal window:
1. Remove the initial join between the two columns by clicking the (minus) icon.
2. Under Join Expressions, click the text box to open the Join Expression interface, where you can specify or update the custom SQL expression that defines the join conditions.
  For example, you can enter the following expression to only show data where the amount of complex carbohydrates equals the amount of sugars, and the calorie content is greater than 250.
```
[Complex Carbohydrates Grams]=[Sugars Grams] AND [cereals_1 Calories] > 250
```
Click Apply to save the expression and return to the Edit Join modal.
In the Edit Join modal, verify that the new join expression appears under Join Expressions and click Apply.
Click Save in the top-right corner.