Using the Expression Builder

The Expression Builder dialog helps you construct expressions for Derive Fields, Filter Rows, Data Quality Analyzer, Filter Existing Rows, and Join nodes. This dialog provides a list of available fields, operators, and functions you can use to build expressions.

To open the Expression Builder dialog, right-click the node and click Configure. In the displayed dialog, select the required field and click Edit.

Click to open the Insert Function dialog, enter a keyword in Search By Keyword field, and click Search to find the function. The Search Results panel provides the list of matching functions.

Click on the required function, and the description for the function is displayed in the right panel. To insert the selected function into the expression, you can either double-click the function or click OK.

Click to check the validity of the expression and report any existing error(s).

Click to view the following in the list:

Views the documentation on aggregation functions when building an aggregation expression.

Views the documentation on expression language. The documentation is also available on the Expression Language page.

The left panel provides the Field References, Operators, Functions, and Constants that can be used to insert into the expression. To insert an element, double-click the element and drag it to the expression or select the element and press the Enter or Space key.

Provides a list of input fields that can be referenced in the expression. The field icon indicates its data type.

Provides a list of operators supported by expression language. The operators are organized by category.

Provides a list of functions available to the expression language, and it is organized by category. To see the description of a function, move the pointer over it. After a function is inserted into the expression, you must replace its argument names with appropriate values.

Provides a list of common constant values used by certain functions. All valid date or time part, granularity values, and valid tz database names for time zones are listed. Note:

• Common date or time and number formats are listed, but many other valid formats are not listed.

You can filter the elements in the tree by prefix. Enter the first few characters of a field, operator, or function in the text box located above the element tree and only the matching elements are displayed. To return to the normal view, delete the contents in the text area. Aggregations – When you are building an aggregation expression, the list of aggregation functions supported by the expression language are provided.

The editor displaying the expression that is built. You can insert the elements from the element tree or type in the editor.