# PERIOD\_DIFF

## Syntax

```sql
PERIOD_DIFF(P1,P2)
```

## Description

Returns the number of months between periods P1 and P2. P1 and P2 can be in the format `YYMM` or `YYYYMM`, and are not date values.

If P1 or P2 contains a two-digit year, values from 00 to 69 are converted to from 2000 to 2069, while values from 70 are converted to 1970 upwards.

## Examples

```sql
SELECT PERIOD_DIFF(200802,200703);
+----------------------------+
| PERIOD_DIFF(200802,200703) |
+----------------------------+
|                         11 |
+----------------------------+

SELECT PERIOD_DIFF(6902,6803);
+------------------------+
| PERIOD_DIFF(6902,6803) |
+------------------------+
|                     11 |
+------------------------+

SELECT PERIOD_DIFF(7002,6803);
+------------------------+
| PERIOD_DIFF(7002,6803) |
+------------------------+
|                  -1177 |
+------------------------+
```

<sub>_This page is licensed: GPLv2, originally from_</sub> [<sub>_fill\_help\_tables.sql_</sub>](https://github.com/MariaDB/server/blob/main/scripts/fill_help_tables.sql)

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