Question: Is there any way to **clear** mysql **query cache** without restarting mySQL server?

Answer: 
I believe you can use...

```
RESET QUERY CACHE;

```

...if the user you're running as has reload rights. Alternatively, you can defragment the query cache via...

```
FLUSH QUERY CACHE;

```

See the [Query Cache Status and Maintenance](http://dev.mysql.com/doc/refman/5.0/en/query-cache-status-and-maintenance.html) section of the MySQL manual for more information.
according the [documentation](http://dev.mysql.com/doc/refman/5.0/en/query-cache-status-and-maintenance.html), this should do it...

```
RESET QUERY CACHE 

```