一般備份有三種類型: Full(完整), Differential(差異), Incremental(增量)
後兩者都是只備份某一次 Full 之後的變更, 但其不同點在於:

1. Differential 是比對備份當下跟當上一次 Full 之間的變更
2. Incremental 是比對備份當下跟上次 Full 之後的最後一次 Incremental 變更

由於 Microsoft SQL 提供的是 Differential 備份類型, 所以你只需要還原 Full 和指定日期的 Differential 就可以了. 這裡有詳細的解釋:
Differential Backups (SQL Server)
關鍵段落在此:

A differential backup captures only the data that has changed since that full backup.

Therefore restoring from a differential backup will necessarily take more steps and time than restoring from a full backup because two backup files are required.

At restore time, before you restore a differential backup, you must restore its base. Then, restore only the most recent differential backup to bring the database forward to the time when that differential backup was created. Typically, you would restore the most recent full backup followed by the most recent differential backup that is based on that full backup.