DATE_FORMAT
Formats a date or datetime value as a specific string.
Overview
DATE_FORMAT is a MySQL function that returns text according to a format string. This example uses %Y-%m for reporting output. Avoid wrapping an indexed date column in DATE_FORMAT for large-table filters; use a date range instead. Other databases use different functions and format tokens.
Basic syntax
SELECT DATE_FORMAT(created_at, '%Y-%m') AS month FROM orders;Examples
DATE_FORMAT example
Format each order created_at value as YYYY-MM and observe the returned month text.
Sample table
Table：
orders| created_at |
|---|
| 2026-01-03 |
| 2026-01-08 |
| 2026-02-02 |
| 2026-02-15 |
Run result
| month |
|---|
| 2026-01 |
| 2026-01 |
| 2026-02 |
| 2026-02 |
Common issues
Should DATE_FORMAT be used in WHERE filters?
Avoid wrapping indexed date columns in DATE_FORMAT in large-table filters because it may hurt index usage.
Does DATE_FORMAT return a date or a string?
It usually returns a formatted string.
Is DATE_FORMAT required for monthly aggregation?
Not always. YEAR/MONTH or date ranges may be better depending on display and performance needs.
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