SQL Table Aliases
A short nickname for a table — barely useful with one table, essential once queries involve more than one.
What & Why
A table alias gives a table a short, temporary nickname for the rest of the query. On a single-table query it just saves typing; once JOINs enter the picture (a later lesson), it becomes essential for telling identically-named columns from different tables apart.
See How It Works
| 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 |
EXAMPLE QUERY
SELECT e.name, e.spend
FROM marketing.campaigns e;RESULT — the alias changes query syntax, not output data
| name | spend |
|---|---|
| Spring Launch | 55000.00 |
| Retention Webinar | 45000.00 |
| Finance Retargeting | 50000.00 |
| Enterprise Search | 60000.00 |
The e alias is valid only inside this query; the real table remains marketing.campaigns.
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