3)
a)
SQL Query:
SELECT w.worker_id, w. first_name, w.last_name
FROM WorkerTable w
JOIN ShiftAssignment sa ON w.worker_id = sa.worker_id
JOIN Shift s ON sa.shift_id = s.shift_id
WHERE DATEPART(dw, s.start_time \( )=2 \)
AND s.start_time \( =( \)
SELECT MIN(start_time)
FROM Shift
WHERE DATEPART \( ( \) dw, start_time \( )=2 \)
)
Relational algebra statement:
\( \pi \) Worker.*
( \( \sigma \) s.start_time \( = \) '08:00:00' \( \wedge \) WEEKDAY(s.start_time \( )=0 \)
(Worker \( \triangle \) ShiftAssignment.worker_id \( = \) Worker. worker_id \( \triangle \) ShiftAssignment.shift_id \( = \) Shift.shift_id))
