MySQL:截断表与从表中删除

Question

我们什么时候使用DELETE命令而不是TRUNCATE命令？我正在尝试在互联网上查找，但两个命令都删除了数据;我分不清其中的区别。

Answer 1

从表中删除

1. DELETE is a DML Command.
2. DELETE statement is executed using a row lock, each row in the table is locked for deletion.
3. We can specify filters in where clause
4. It deletes specified data if where condition exists.
5. Delete activates a trigger because the operation are logged individually.
6. Slower than truncate because, it keeps logs.
7. Rollback is possible.
8. LIMIT clause can also be used to set a limit on the number of rows to be deleted.
9. ORDER BY clause can be used in DELETE statement. In this case, the rows are deleted in the specified order.

凹槽表

1. TRUNCATE is a DDL command.
2. TRUNCATE TABLE always locks the table and page but not each row.
3. Cannot use Where Condition.
4. It Removes all the data reset the auto increment number.
5. TRUNCATE TABLE cannot activate a trigger because the operation does not log individual row deletions.
6. Faster in performance wise, because it doesn't keep any logs.
7. Rollback is possible.
8. Cannot use LIMIT and ORDER BY.

删除和TRUNCATE在与TRANSACTION一起使用时都可以回滚。如果存在具有自动增量的主键，则截断将重置计数器。