SQL COUNT DISTINCT
Counts unique values only — repeats collapse down to one before counting.
What & Why
COUNT(DISTINCT column) counts how many different values appear — duplicates get counted once, no matter how many times they repeat.
See How It Works
BUSINESS QUESTION
How many distinct channels are represented?
| id | name | channel | spend | start_date | end_date | status | target_segment |
|---|---|---|---|---|---|---|---|
| 1 | Spring Launch | google_ads | 55000.00 | 2024-01-15 | 2024-03-31 | active | smb |
| 2 | Retention Webinar | 45000.00 | 2024-02-10 | 2024-04-15 | active | enterprise | |
| 3 | Finance Retargeting | 50000.00 | 2024-03-12 | 2024-05-31 | active | enterprise | |
| 4 | Enterprise Search | google_ads | 60000.00 | 2024-04-01 | 2024-06-30 | active | enterprise |
Watch duplicate channels collapseRow 1 of 4
COUNT(DISTINCT channel)
| row | campaign | channel | spend | distinct |
|---|---|---|---|---|
| 1 | Spring Launch | google_ads | 55,000 | +1 |
| 2 | Retention Webinar | 45,000 | WAIT | |
| 3 | Finance Retargeting | 50,000 | WAIT | |
| 4 | Enterprise Search | google_ads | 60,000 | WAIT |
Running result
COUNT(DISTINCT channel) = 1google_ads appears for the first time, so the distinct count becomes 1.
EXAMPLE QUERY
SELECT COUNT(DISTINCT channel) AS distinct_channels
FROM marketing.campaigns;Sign up free to try it on a real business scenario