SQL Fundamentals · Database Basics · Lesson 3 of 17
Common Data Types
Concept
Common Data Types
INT stores whole numbers, VARCHAR stores variable-length text, and DATE stores calendar dates — picking the right type keeps data consistent.
By the end of this lesson
- Explain the core idea behind Common Data Types.
- Predict output before running a change.
- Test one realistic and one unusual input.
- Use the result to make the next decision.
How to study this page
- 1. Read one concept.
- 2. Change the example.
- 3. Run, compare, and explain.
- 4. Complete the challenge below.
Self-check before continuing
Without looking at the example, describe what changes when you modify one input in Common Data Types. Then reopen the editor and prove your explanation with a small test.
You are ready to continue when you can predict, test, and explain the result.
Your turn
Add a VARCHAR column for a status field to the enrollments table above.
Need a nudge?
Ask about this lesson or your next move. The guide explains the path without taking the work away from you.
Ready for the next lesson?
Mark this lesson complete when you have finished the exercise.
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