Adding Filter
The Filter operation enables users to specify a WHERE clause for the dataset, thereby limiting the number of rows returned. Follow these steps to define a filter in the data flow:
1. Drag the Filter operation from the Operations palette and drop it in the canvas. By default the name of the node is set as “Filter”. Click on the name to change it.
2. Filter operations can be connected to another operation by dragging the filter operation towards any other operation you wish to apply the filter.
3. Once the Filter operation is added to your data flow diagram, the Filter Configuration pane is displayed below the canvas.
4. You can add as many filters as needed to construct your WHERE clause and build your query. Click on the + button to add more conditions. The following operators and conjunctions are supported in the Filter node:
— = (Equal)
— > (Greater than)
— < (Less than)
— <= (Less than or Equal)
— >= (Greater than or Equal)
— <> (Not Equal)
— LIKE
— BETWEEN
— IN
— IS NULL
— IS NOT NULL
— AND
— OR
— AND NOT
5. Click on the “Write an Expression” option in the field specific drop down list, to write your own expression. The Expression editor window is displayed.
6. Click on the helper tools icon to view the list of functions supported. The Expression editor is a self-service tool that lets you build your expression. Refer to the chapter SQL Functions in the TDV Reference Guide, for a list of the supported functions.
7. After the WHERE clause is successfully built, the data preview pane on the right displays the result set. Data in the preview pane can be sorted.
Features and Limitations of the Filter Operation
• The Filter operation can have only one input and one output.
• This operation can be added after any operation except the Publish operation.