2013 - Lost connection to MySQL server during query

select c.categories_id, cd.categories_name, c.parent_id from categories c, categories_description cd where c.categories_status = '1' and c.parent_id = '998' and c.categories_id = cd.categories_id and cd.language_id='1' order by sort_order, cd.categories_name

[XT SQL Error]

2006 - MySQL server has gone away

select count(*) as total from sessions where sesskey = '0a4ea6bcb0b987346deefdaad7af9ec9'

[XT SQL Error]