1. Table deduplication operation
2. Group Statistics
1) The project has no plan [there is no corresponding record in the projectplan table or the status is 0]
SELECT project.Name, CASE MAX( CASE WHEN projectplan.`Status`>0 THEN 1 ELSE 0 END ) WHEN 1 THEN 'Project Plan' ELSE 'No Project Plan' END FROM project LEFT JOIN projectplan ON project.ID=projectplan.ProjectID GROUP BY project.ID
SELECT project.ID FROM project WHERE EXISTS (SELECT 1 FROM projectplan WHERE projectplan.ProjectID=project.ID AND projectplan.Status>0)The number of activities in the 2 major stages < 2 [query the number of activities at the first level]
SELECT project.Name,COUNT(planitem.ID) FROM project LEFT JOIN planitem ON project.id = planitem.project_id WHERE planitem.LEVEL = 1 GROUP BY project.ID HAVING COUNT(planitem.ID)>= 2