SQL COUNT / COUNT(*)
Counts rows — COUNT(*) counts every row regardless of what's in it.
What & Why
COUNT(*) counts every row in the result, full stop — it doesn't look at any particular column's values, so a row full of NULLs still counts as one row.
See How It Works
BUSINESS QUESTION
How many campaigns are there in total?
| 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 the count accumulate, row by rowRow 1 of 4
COUNT(*)
| row | campaign | channel | spend | count(*) |
|---|---|---|---|---|
| 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(*) = 1Spring Launch contributes one complete row, raising COUNT(*) to 1.
EXAMPLE QUERY
SELECT COUNT(*) AS total_campaigns
FROM marketing.campaigns;Now You Try
Practice this concept
Marketing wants the total number of campaign rows currently stored, including rows whose optional fields are NULL.
Available schema
marketingPrefix tables with marketing.table_name.
total_campaignsmarketing.campaigns| Column | Type |
|---|---|
| id | integer |
| name | text |
| channel | text |
| spend | numeric |
| start_date | date |
| end_date | date |
| status | text |
| target_segment | text |
| legacy_id | text |
query.sql
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