Lesson 04 — Column Types | Coda Mastery Course

01 — Why Types Matter

The right type makes formulas reliable.

Column types aren't just formatting. They control what formulas you can run, how filters work, and how the UI presents data. A date stored as text can't be used in DateAdd(). A number stored as text can't be summed. Getting types right from the start saves hours of debugging later.

Rule of thumb If you're going to do math on it → Number. If you're going to sort or filter by time → Date. If there's a fixed list of values → Select. Everything else → Text.

02 — Core Types

The types you'll use every day.

Column Type Reference

Column Type	Stores	Use when…	Example
Text	Any string	Names, notes, descriptions	"Website redesign"
Number	Integer or decimal	Quantity, price, score, %, duration	4500, 0.85, 12
Date	Date/datetime	Deadlines, created dates, log timestamps	Apr 15 2025
Checkbox	true / false	Done/not done, yes/no flags	☑ / ☐
Select	One value from a list	Status, priority, category, type	In Progress, High
Select List	Multiple values from a list	Tags, skills, labels (multi-select)	Design, Frontend
Relation	Row(s) from another table	Linking records across tables	→ Alice (in Team table)
Person	Workspace member	Assignees, owners, reviewers	@Alice
URL	Web link	Resource links, doc references	https://…
Button	Action trigger	Inline clickable workflow actions	▶ Run action
AI	AI-generated text	Summaries, classifications, extractions	"Positive sentiment"

03 — Select Columns

Select vs Select List vs Text

New Coda users often use Text columns where a Select would serve them better. The difference matters:

✗ Text for status

Alice types: "in progress"
Bob types: "In Progress"
Carol types: "active"

Three different values. Filtering by "In Progress" misses two rows. Grouping produces three groups instead of one.

✓ Select for status

To Do In Progress Done Blocked

Fixed options. Every row uses the same value. Filters, groups, and board views all work reliably.

04 — Relation Columns

The column that connects tables.

Relation columns are the foundation of Coda's relational model. Instead of typing a project name into a Tasks row, you reference the actual Projects row. This means:

Rename the project once and it updates everywhere
You can pull any field from the related row using a Lookup column
You can show all related tasks from the project side with a linked relation (reverse lookup)

Tasks → Projects relation

Task	Project Relation	Due	Status
Write copy	Website redesign	Apr 10	Done
Design mockups	Website redesign	Apr 12	In Progress
Write email blast	Q2 campaign	Mar 28	Done

The "Project" column references rows in the Projects table — not just text strings. Click any pill to open that project's detail view.

Practice

Column type quiz.

Column Types

5 Questions

Question 1 of 5

You're tracking project budget amounts like $4,500 and $12,000. Which column type should you use?

✓ Number — use this for any value you'll calculate, sum, or compare mathematically. Text would prevent formulas from working on it.

Question 2 of 5

You want to tag tasks with multiple labels like "Design", "Frontend", "Research". Which column type supports multiple values?

✓ Select List (multi-select) — allows picking multiple values from a predefined list. Regular Select only allows one.

Question 3 of 5

You want to link each Task row to its parent Project in the Projects table. Which column type enables this?

✓ Relation column — links to actual rows in another table. This enables cross-table references, Lookup columns, and bidirectional relationships.

Question 4 of 5

Why is Select better than Text for a Status column?

✓ Consistency — Select limits values to a predefined list, making filters, groups, and board views work reliably across all users.

Question 5 of 5

An AI column in Coda is used to:

✓ AI columns run AI prompts on each row's data — summarizing long text, classifying sentiment, extracting entities, or generating content based on a custom prompt.