# Issue sorting Clients by latest Appointment when using Big Tables

**URL:** <https://community.glideapps.com/t/issue-sorting-clients-by-latest-appointment-when-using-big-tables/86039>\
**Category:** Ask for Help\
**Created:** [January 15, 2026, 2:48pm UTC](https://community.glideapps.com/t/issue-sorting-clients-by-latest-appointment-when-using-big-tables/86039 "2026-01-15T14:48:32Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![cgiudice8b](https://avatars.discourse-cdn.com/v4/letter/c/fbc32d/32.png) [@cgiudice8b](https://community.glideapps.com/u/cgiudice8b)\
**Post date:** [January 15, 2026, 2:48pm UTC](https://community.glideapps.com/t/issue-sorting-clients-by-latest-appointment-when-using-big-tables/86039/1 "2026-01-15T14:48:32Z")

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I’m having an issue sorting a collection when the data source is a Glide Table that relies on computed columns linked to a Big Table.

**Context**  
• I’m building a CRM to manage **Clients** and **Appointments**  
• Main tables:  
• **Clients**  
• **Appointments** (Big Table, expected 50k+ rows)  
• Users need to quickly see how long it has been since the last **completed** appointment with each client  
• Appointments can be:  
• completed  
• not completed  
• planned in the future (it’s just a future appointment with completed not true)

**Current setup**  
• A Glide Table (Clients → Big Table) linked to the **Appointments** Big Table  
• In the Clients table I created:  
• a **Lookup** column that retrieves only completed appointments for each client  
• a **Single Value** column that extracts the most recent completed appointment  
• Data retrieval works as expected

**Problem**  
• I can’t sort a collection based on the latest appointment date coming from these computed columns  
• I tried multiple approaches (lookup, single value, different source columns), but sorting doesn’t work when the data originates from a Big Table

**Goal**  
• calculate how many days have passed since the last completed appointment  
• assign a frequency/status label (e.g. recent / overdue)  
• sort clients by their most recent appointment

Is this a known limitation when working with Big Tables, or is there a recommended data modeling pattern or workaround to achieve this?

Thanks in advance for any suggestions or best practices.

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**Author:** ![John\_Marshall](https://sea2.discourse-cdn.com/flex002/user_avatar/community.glideapps.com/john_marshall/32/91237_2.png) [@John\_Marshall](https://community.glideapps.com/u/John_Marshall)\
**Post date:** [January 15, 2026, 5:06pm UTC](https://community.glideapps.com/t/issue-sorting-clients-by-latest-appointment-when-using-big-tables/86039/2 "2026-01-15T17:06:56Z")

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Big Tables cannot sort on calculated fields, so the workaround is to use a workflow to assign a calculated value to a basic column which can then be used as a sort field.