Add content to subdate

content/sql/concepts/dates/terms/subdate/subdate.md

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+---
+Title: 'SUBDATE()'
+Description: 'Subtract a specific time interval (like days, months, or years) from a given date.'
+Subjects:
+  - 'Computer Science'
+  - 'Data Science'
+Tags:
+  - 'Database'
+  - 'Queries'
+  - 'MySQL'
+CatalogContent:
+  - 'learn-sql'
+  - 'paths/analyze-data-with-sql'
+---
+
+The **`SUBDATE()`** function returns a date or datetime value after subtracting a specified time interval from a starting date. It is commonly used in queries that need to calculate past dates, such as filtering records from a certain number of days, months, or years before a given date.
+
+## Syntax
+
+```pseudo
+SUBDATE(date, INTERVAL value unit)
+```
+
+Or, alternatively:
+
+```pseudo
+SUBDATE(date, days)
+```
+
+**Parameters:**
+
+- `date`: The starting `DATE` or `DATETIME` value.
+- `value`: The amount of time to subtract.
+- `unit`: The unit of time to subtract, such as `DAY`, `MONTH`, `YEAR`, or `HOUR`.
+- `days`: An integer value representing the number of days to subtract.
+
+**Return value:**
+
+- Returns a `DATE` when the input is a date.
+- Returns a `DATETIME` when the input includes a time component.
+
+## Example 1: Subtracting a Month from a Date
+
+In this example, `SUBDATE()` subtracts one month from a given date and returns the resulting date:
+
+```sql
+SELECT SUBDATE('2026-01-21', INTERVAL 1 MONTH);
+```
+
+The output of this code is:
+
+```shell
+2025-12-21
+```
+
+## Example 2: Shorthand Syntax (Days Only)
+
+In this example, `SUBDATE()` subtracts a specified number of days from a date using the shorthand numeric syntax:
+
+```sql
+SELECT SUBDATE('2026-01-21', 10);
+```
+
+The output of this code is:
+
+```shell
+2026-01-11
+```
+
+## Example 3: Using Different Time Units
+
+In this example, `SUBDATE()` subtracts different time units such as years and hours from date and datetime values, including the current date and time:
+
+```sql
+SELECT SUBDATE('2026-05-15', INTERVAL 1 YEAR);
+SELECT SUBDATE('2026-01-21 12:00:00', INTERVAL 3 HOUR);
+SELECT SUBDATE(NOW(), INTERVAL 1 HOUR);
+```
+
+The output of this code is:
+
+```shell
+2025-05-15
+2026-01-21 09:00:00
+2026-01-22 11:05:30
+```