Could not Import data back to the original table

Could not Import data back to the original table

Steps:
1, Create a table via SQL and Upsert a few lines of data;
2, Export table data using hbase Export;
3, Delete the table data via SQL: delete from TAB1;
4, Try to Import data back to the original table;
No data imported!

5, Only if drop the table and create the table again, then could import the data.