sql - MySQL how do I select missing values -

i have table contains employees , task, , want list of missing employee/task combinations.

bob  gardening bob  watering jane gardening jane digging 

so select yield

bob  digging jane watering 

any suggestions? thanks

you need take employees 1 subquery , tasks 1 more subquery , cross join. once done give condition below.

select * ( select a.employee,b.task (select distinct employee table) a, (select distinct task table) b) (employee,task) not in (select employee, task table)