Joining tables together in a model function

[eluser]jpidgeon[/eluser]
CRITERIA TABLE

criteria_id JOINED
criteria_name
criteria_description
criteria_order
criteria_kpi1
criteria_kpi2
criteria_kpi3
criteria_kpi4
criteria_kpi5
task_id JOINED

DATA TABLE

data_id
qms_id
staff_id
criteria_id JOINED
kpi1
kpi2
kpi3
kpi4
kpi5
comments
develop
dev_action
dev_result
dev_target
dev_completed

TASKS TABLE

task_id JOINED
task_name


So I'm normally sending in the data.qms_id and criteria.task_id, which would return the 40 or so rows in the criteria table, but as there are no rows currently existing in the data table - nothing shows. Rows of data are only added here once I save the form.