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title: "Table Calculations in Reporting"
canonical: "https://hub.freewheel.tv/space/BC/115179736/Table%20Calculations%20in%20Reporting"
format: markdown
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Overview Table calculations provide a powerful way to derive new data within a data visualization without altering the underlying dataset. These calculations are performed on the result set after all other SQL calculations have been executed, allowing for dynamic and flexible analysis directly within the report builder's interface. Table calculations are custom calculations created directly within the report builder to perform calculations on data returned by a query. These calculations create the ability to compute new fields, metrics, or aggregations based on existing data in the result set, providing a high degree of flexibility for analysis. When writing custom calculations using this tool, a wide range of mathematical, statistical, and conditional functions may be defined, and there can be a specific context entered for how these calculations may be performed. For example, calculations can be applied to a specific dimension, dimension group, or across entire data sets. Table calculations may help with viewing various analytical tasks, such as year-over-year comparisons and trend analysis, assisting in future decision-making. How to use Table Calculations To utilize table calculations in Report Builder, click the  +Add  button next to the  Custom Fields  dropdown on the left side panel of the report view. From this view, select  Table Calculation . A window will appear to create a table calculation. A type of calculation must be selected to apply to the report. Below are the types of calculations that are selectable: Calculation Type Definition % of column The row value divided by the sum of values in the column. (Only includes values in the data table when the row limit has been reached). % of previous row Current row’s value divided by the value of the row below. % change from previous row Difference between the current row’s value and value of the row below, divided by the value of the row below. Rank of Column Rank of row’s value among all values in the column (Only includes values in the data table when the row limit has been reached). Running column total Cumulative sum of this row and all previous rows in the column. Custom expression Add a custom expression, or edit an existing expression in the free field text box. Once the table calculation has been created, click  Save  to view the custom data in the report. For more information on using table calculations in Report Builder, see these  external sources:   Using Table Calculations  and  Looker Functions and Operators . Reporting Considerations Row Limits and Table Calculations Table calculations are applied to the rows returned by a query result. This means if a table calculation references  Campaign ID , then  Campaign ID  needs to also be included in the query as a dimension (columns can subsequently be hidden from visualizations). If the query hits a row limit, the table calculation is only applied to those rows displayed. Table calculations that are applied to the displayed query results affect their compatibility with some methods of generating and sharing query results. When getting results from Report Builder, whether via an ad-hoc query or a scheduled report, there is an option to include  All Results  instead of  Results in Table . In order to use the  All Results  option, the query cannot contain table calculations. For reporting API users: the way that the row limit is set varies slightly by endpoint: For  reporting/report-schedules/*  endpoints: the parameter is  send_all_results . For  reporting/run-query and /reporting/run-saved-report  endpoints: the parameter is  limit . Table calculations will be returned when there is a row limit applied to the query, whether that is set via the API at query submission time (via the  limit  parameter) or set via the underlying Look’s row limit. Other Considerations The following are smaller considerations to keep in mind when creating a table calculation: When adding a Total row to the data table, some table calculations that perform aggregations might not add up as expected. For example, this is the case for calculations that use "percentile" or "median". This is because table calculations calculate totals using the values in the Total row, not by using the values in the data column. If table calculation #1 is being referenced by table calculation #2 and the name of table calculation #1 is changed, table calculation #2 will return errors until the name is updated in its definition.