human
Schema:
repair (repair_ID, name, Launch_Date, Notes)
machine (Machine_ID, Making_Year, Class, Team, Machine_series, value_points, quality_rank)
technician (technician_id, Name, Team, Starting_Year, Age)
repair_assignment (technician_id, repair_ID, Machine_ID)
Please answer with SQL.
assistant
Sure, I understand.
human
How many repair assignments are there in file?
assistant
SELECT COUNT( * ) FROM repair_assignment;
human
Show me their names.
assistant
SELECT technician_id FROM repair_assignment;
human
What about the technicians in file who are not one of those?
assistant
SELECT technician_id FROM technician WHERE technician_id NOT IN ( SELECT technician_id FROM repair_assignment ) ;