# Creating a Time Based Column Filter

Some time-related columns in your parent segment, will contain a Unix time value. However, in order for Treasure Data to filter these columns using time-based operators (e.g., "on or after date," "between dates," etc.) these columns must be identified as, or be converted to, type timestamp.

Unix time columns can be converted to timestamp in the following ways:

* [Creating a Time-based Column Filter in Treasure Console](/products/customer-data-platform/audience-studio/segment/rule-operator/creating-a-time-based-column-filter-in-td-console)
* [Creating a Time-based Column Filter Using a REST API](/products/customer-data-platform/audience-studio/segment/rule-operator/creating-a-time-based-column-filter-using-a-rest-api)


## Prerequisites

* Only columns that contain Unix time can be converted to timestamp. Unix time is stored as a 10-digit number (e.g. 1691244585). In the Treasure Console, these Unix time columns are usually of type long or string (??).


## Limitations

* Treasure Data does not support "all columns" set to true in the Parent Segment’s behavior configuration. Instead, choose "columns."


## Further Reading

* For a high-level overview of this concept, see [Customizing Behavior and Attribute Columns for Segment Rules](/products/customer-data-platform/audience-studio/segment/rule-operator/customizing-behavior-and-attribute-columns-for-segment-rules).