配置单元首选或sql删除时间重叠

catagory1 catagory2 timestart time_end  
1         A        4:00     5:00
1         A        2:30     4:30
1         A        3:30     5:00
1         A        5:00     7:00
1         A        8:00     9:00
2         A        4:00     5:00
1         B        4:00     5:00

按类别1类别2从单个表组中删除时间重叠
结果看起来像

catagory1 catagory2 timestart time_end  
1         A        4:00        5:00
1         A        5:00        7:00
1         A        8:00        9:00
2         A        4:00        5:00
1         B        4:00        5:00