# grouped(by:timeUnit:) Creates a grouping of rows that the method selects by choosing unique units of time in a date column you select by column identifier. ``` func grouped(by columnID: ColumnID, timeUnit: Calendar.Component) -> RowGrouping ``` ## Parameters `columnID` A column identifier. `timeUnit` A component of a calendar date. ## Return Value A collection of groups. ## Discussion After the method aggregates the groups, it creates a column with the same name as the original column plus the `timeUnit` name. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)