# WEEK

## Syntax

```sql
WEEK(date[,mode])
```

## Description

This function returns the week number for `date`. The two-argument form of`WEEK()` allows you to specify whether the week starts on Sunday or Monday and whether the return value should be in the range from 0 to 53 or from 1 to 53. If the `mode` argument is omitted, the value of the [default\_week\_format](https://mariadb.com/docs/server/server-management/variables-and-modes/server-system-variables#default_week_format) system variable is used.

### Modes

| Mode | 1st day of week | Range | Week 1 is the 1st week with |
| ---- | --------------- | ----- | --------------------------- |
| 0    | Sunday          | 0-53  | a Sunday in this year       |
| 1    | Monday          | 0-53  | more than 3 days this year  |
| 2    | Sunday          | 1-53  | a Sunday in this year       |
| 3    | Monday          | 1-53  | more than 3 days this year  |
| 4    | Sunday          | 0-53  | more than 3 days this year  |
| 5    | Monday          | 0-53  | a Monday in this year       |
| 6    | Sunday          | 1-53  | more than 3 days this year  |
| 7    | Monday          | 1-53  | a Monday in this year       |

With the mode value of 3, which means 'more than 3 days this year', weeks are numbered according to ISO 8601:1988.

## Examples

```sql
SELECT WEEK('2008-02-20');
+--------------------+
| WEEK('2008-02-20') |
+--------------------+
|                  7 |
+--------------------+

SELECT WEEK('2008-02-20',0);
+----------------------+
| WEEK('2008-02-20',0) |
+----------------------+
|                    7 |
+----------------------+

SELECT WEEK('2008-02-20',1);
+----------------------+
| WEEK('2008-02-20',1) |
+----------------------+
|                    8 |
+----------------------+

SELECT WEEK('2008-12-31',0);
+----------------------+
| WEEK('2008-12-31',0) |
+----------------------+
|                   52 |
+----------------------+

SELECT WEEK('2008-12-31',1);
+----------------------+
| WEEK('2008-12-31',1) |
+----------------------+
|                   53 |
+----------------------+

 SELECT WEEK('2019-12-30',3);
+----------------------+
| WEEK('2019-12-30',3) |
+----------------------+
|                    1 |
+----------------------+
```

```sql
CREATE TABLE t1 (d DATETIME);
INSERT INTO t1 VALUES
    ("2007-01-30 21:31:07"),
    ("1983-10-15 06:42:51"),
    ("2011-04-21 12:34:56"),
    ("2011-10-30 06:31:41"),
    ("2011-01-30 14:03:25"),
    ("2004-10-07 11:19:34");
```

```sql
SELECT d, WEEK(d,0), WEEK(d,1) from t1;
+---------------------+-----------+-----------+
| d                   | WEEK(d,0) | WEEK(d,1) |
+---------------------+-----------+-----------+
| 2007-01-30 21:31:07 |         4 |         5 |
| 1983-10-15 06:42:51 |        41 |        41 |
| 2011-04-21 12:34:56 |        16 |        16 |
| 2011-10-30 06:31:41 |        44 |        43 |
| 2011-01-30 14:03:25 |         5 |         4 |
| 2004-10-07 11:19:34 |        40 |        41 |
+---------------------+-----------+-----------+
```

<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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