SELECT pj.type AS type, count( pj.id ) AS project_count, count( evt.id ) AS alarm_count, ( SELECT count(id) from t_device where type=1) as camera_count, ( SELECT count(id) from t_device where type=2) as ai_box_count, ( SELECT count(id) from t_device where type=3) as radar_count, ( SELECT count(id) from t_device where type=4) as sensor_count, ( SELECT count(evt.id) FROM t_probably where project=pj.id AND status <> 1 and status is not null ORDER BY alarm_time DESC LIMIT 1 ) AS dissipate_event FROM t_project AS pj LEFT JOIN t_device AS dev ON pj.id = dev.project LEFT JOIN t_probably AS evt ON pj.id = evt.project LEFT JOIN t_organize AS org ON pj.organize = org.id ORDER BY pj.type DESC 在这段sql中，为什么project_count的数据和表里数据数量不一致

可能是因为在 JOIN 表时，有些项目（t_project）没有对应的设备（t_device）或报警（t_probably），这些项目在统计 project_count 时会被算作 0，导致最终的 project_count 数量和表中的数据数量不一致。另外，如果在 t_project 表中有重复的 id，也会导致最终的统计结果与表中的数据数量不一致。