SLEEP()

Description

Sleeps (pauses) for the number of seconds given by the duration argument, then returns 0.

Syntax

>
SLEEP(duration)

Arguments

Arguments	Description
duration	Required. The number of seconds. The `duration` may have a fractional part. The `duration` is not allowed NULL or negative.

Returned Value

When sleep returns normally (without interruption), it returns 0.
When SLEEP() returns 1 (with interruption or time out), the query returns no error.

For example:
1. In session 1, execute the following command to query the current connection_id and execute the SLEEP() function:
  
  sql  mysql> select connection_id(); +-----------------+ | connection_id() | +-----------------+ | 1476 | +-----------------+ 1 row in set (0.03 sec) mysql> select sleep(200);
2. At this point, open a new session, interrupt session 1, and run the following command.
  
  sql  mysql> kill 1463; Query OK, 0 rows affected (0.00 sec)
3. Check the query result of session 1:
```
mysql> select sleep(200);
+------------+
| sleep(200) |
+------------+
|          1 |
+------------+
1 row in set (26.50 sec)
```

When SLEEP() returns an error (part of a query is uninterrupted). For example:

mysql> SELECT 1 FROM t1 WHERE SLEEP(1000);
ERROR 20101 (HY000): internal error: pipeline closed unexpectedly

Examples

```sql -- without interruption mysql> SELECT SLEEP(1); +----------+ | sleep(1) | +----------+ | 0 | +----------+ 1 row in set (1.01 sec)

-- without interruption mysql> SELECT SLEEP(1000); +-------------+ | sleep(1000) | +-------------+ | 0 | +-------------+ 1 row in set (18 min 20.87 sec)

create table t1 (a int,b int); insert into t1 values (1,1),(1,null); mysql> select sleep(a) from t1; +----------+ | sleep(a) | +----------+ | 0 | | 0 | +----------+ 2 rows in set (2.01 sec) ```