# Interval Keyword
__*INTERVAL*__
+ `INTERVAL` is a keyword used to specify the duration
+ `INTERVAL` is not a data type
+ e.g:
  + `SELECT '2021-01-01' + INTERVAL 10 DAY, '2021-01-01' + INTERVAL '5 2:3:4' DAY_SECOND;` 
```
tidb> SELECT '2021-01-01' + INTERVAL 10 day, '2021-01-01' + INTERVAL '5 2:3:4' DAY_SECOND;
+--------------------------------+----------------------------------------------+
| '2021-01-01' + INTERVAL 10 day | '2021-01-01' + INTERVAL '5 2:3:4' DAY_SECOND |
+--------------------------------+----------------------------------------------+
| 2021-01-11                     | 2021-01-06 02:03:04                          |
+--------------------------------+----------------------------------------------+
1 row in set (0.00 sec)
```

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For more information, see More about INTERVAL in the function section.