Including records that are missing in another dataset - sql

Question

I'm trying to do something along the lines of a WHERE NOT EXISTS or WHERE NOT IN, but am struggling with the syntax.
This is the results set I've got so far, let's called it PlanActStaff:
SELECT
CTE_PlanStaff.RegisterID,
CTE_PlanStaff.TT_ActivityDate,
CTE_PlanStaff.TT_ActivityTime,
CTE_PlanStaff.TT_StaffID,
CTE_ActStaff.ActStaffID
FROM
CTE_PlanStaff
INNER JOIN
CTE_ActStaff
ON
CTE_PlanStaff.RegisterID = CTE_ActStaff.RegisterID
AND
CTE_PlanStaff.TT_ActivityDate = CTE_ActStaff.ActSessionDate
AND
CTE_PlanStaff.TT_ActivityTime = CTE_ActStaff.ActSessionStartTime
For each record in this result set I want the query to go back and check my CTE_PlanStaff CTE to see whether the ActStaffID exists for the current combination of RegisterID, TT_ActivityDate and TT_ActivityTime in CTE_PlanStaff.
So for example, if a record being checked in PlanActStaff looked like this:
| RegisterID | TT_ActivityDate | TT_ActivityTime | TT_StaffID | ActStaffID |
|------------|-----------------|-----------------|------------|------------|
| 98688 | 2016-01-04 | 11:20 | 2453 | 2067 |
CTE_PlanStaff would then be filtered on the same combination of RegisterID, TT_ActivityDate and TT_ActivityTime, so CTE_PlanStaff might then have these records to compare:
| RegisterID | TT_ActivityDate | TT_ActivityTime | TT_StaffID |
|------------|-----------------|-----------------|------------|
| 98688 | 2016-01-04 | 11:20 | 2500 |
| 98688 | 2016-01-04 | 11:20 | 2453 |
I'd then like the ActStaffID value of 2067 checked against each TT_StaffID in the filtered CTE_PlanStaff and if the ActStaffID isn't listed to leave that record showing in my PlanActStaff query.
I've tried to adapt PlanActStaff as follows...
SELECT *
FROM
(
SELECT
CTE_PlanStaff.RegisterID,
CTE_PlanStaff.TT_ActivityDate,
CTE_PlanStaff.TT_ActivityTime,
CTE_PlanStaff.TT_StaffID,
CTE_ActStaff.ActStaffID
FROM
CTE_PlanStaff
INNER JOIN
CTE_ActStaff
ON
CTE_PlanStaff.RegisterID = CTE_ActStaff.RegisterID
AND
CTE_PlanStaff.TT_ActivityDate = CTE_ActStaff.ActSessionDate
AND
CTE_PlanStaff.TT_ActivityTime = CTE_ActStaff.ActSessionStartTime
) PlanActStaff
WHERE
ActStaffID NOT IN (
SELECT *
FROM
CTE_PlanStaff
WHERE
CTE_PlanStaff.RegisterID = PlanActStaff.RegisterID
AND
CTE_PlanStaff.TT_ActivityDate = PlanActStaff.TT_ActivityDate
AND
CTE_PlanStaff.TT_ActivityTime = PlanActStaff.TT_ActivityTime
)
...but I get the following error:
Only one expression can be specified in the select list when the
subquery is not introduced with EXISTS.
I started looking at WHERE NOT EXISTS, but I can't figure out how to both filter CTE_PlanStaff against the current record and then check the staffID fields.

Answer 1

WHERE
ActStaffID NOT IN (
SELECT *
FROM
CTE_PlanStaff
WHERE
CTE_PlanStaff.RegisterID = PlanActStaff.RegisterID
AND
CTE_PlanStaff.TT_ActivityDate = PlanActStaff.TT_ActivityDate
AND
CTE_PlanStaff.TT_ActivityTime = PlanActStaff.TT_ActivityTime
)
you should select only one field to be compared against 'ActStaffID'