Creating Columns in Workbench 4 Using Calculations
You can create new columns in DataSets in Workbench 4 by building calculations based on the data in other columns. For example, you might have a column containing values with one or more decimal places. You could create a new column in which all of the values in the original column are rounded up or down to the nearest whole number, using the CEILING or FLOOR functions, respectively. Workbench 4 contains over 80 such functions you can use in constructing calculations. Categories of functions include logical (such as AND, NOT, IF, etc.), mathematical (such as ACOS, RND, and SUMLIST), statistical (such as AVERAGE, MAX, and STDEV), text (such as CONCATENATE, MID, and SUBSTITUTE), and date and time (such as DAY, EOMONTH, and TODAY). You can find descriptions of all of the functions in the Workbench 4 user interface.
Training Video  Creating Columns in Workbench Using Calculations
Learn how to create new Workbench columns using calculations.
Note: The product training videos are for Domo customers and clients only.
You build calculated fields for a selected DataSet job in the Calculation Builder. You access the Calculation Builder for a DataSet by adding a Calculation transform.
To add a calculated field in Workbench 4,

In the Accounts pane, select the DataSet job you want to add a calculated field to.

In the Transforms grouping in the Buttons toolbar at the top of the Workbench window, click Add New.

In the Transform Type menu, select Calculation then click Next.

Click Finish.
A Calculation item is added under Transforms for this DataSet job. 
Click the new Calculation item under Transforms.
The Calculation Builder opens in the Dynamic Options panel. 
Enter a name for the calculation in the Column Name field.

Build your calculation in the Calculation field using the column names in the Available Fields listing and the functions in the Available Functions listing.
You can add column names and functions to a calculation by doubleclicking them in the list.
You can filter the functions by category by selecting the desired category in the Category menu. All functions are accompanied by descriptions; you can see the description for a function by clicking that function. In addition, each function shows its proper usage. For example, the SUM function is represented as SUM (p1, [p2],...). This means that you are summing the values in all referenced columns, which are indicated by p1, p2, and so on. 
Click Validate to ensure that your calculation is valid.
Note: In calculations, column names cannot contain nonASCII characters. You can reference a column in a calculation using Column# where # is the 1based column order. For example: CONCATENATE(Column2,Column3) 
Click Save in the DataSet Jobs grouping in the Buttons toolbar at the top of the Workbench window.
Your DataSet now contains the new column based on your calculation.