是的，DELETE比较慢，TRUNCATE比较快。为什么?

DELETE必须读取记录，检查约束，更新块，更新索引，并生成重做/撤销。所有这些都需要时间。

TRUNCATE只是在数据库中为表(High Water Mark)调整一个指针，然后!数据不见了。

这是Oracle特有的，AFAIK。

TRUNCATE是DDL语句，而DELETE是DML语句。以下是两者的区别:

As TRUNCATE is a DDL (Data definition language) statement it does not require a commit to make the changes permanent. And this is the reason why rows deleted by truncate could not be rollbacked. On the other hand DELETE is a DML (Data manipulation language) statement hence requires explicit commit to make its effect permanent. TRUNCATE always removes all the rows from a table, leaving the table empty and the table structure intact whereas DELETE may remove conditionally if the where clause is used. The rows deleted by TRUNCATE TABLE statement cannot be restored and you can not specify the where clause in the TRUNCATE statement. TRUNCATE statements does not fire triggers as opposed of on delete trigger on DELETE statement

这里有一个非常好的与主题相关的链接。

TRUNCATE是快的，DELETE是慢的。

尽管TRUNCATE没有问责制。

Truncate and Delete in SQL are two commands which is used to remove or delete data from table. Though quite basic in nature both Sql commands can create lot of trouble until you are familiar with details before using it. An Incorrect choice of command can result is either very slow process or can even blew up log segment, if too much data needs to be removed and log segment is not enough. That's why it's critical to know when to use truncate and delete command in SQL but before using these you should be aware of the Differences between Truncate and Delete, and based upon them, we should be able to find out when DELETE is better option for removing data or TRUNCATE should be used to purge tables.

参考资料请点击这里

简而言之，truncate不会记录任何内容(因此更快，但不能撤消)，而delete会记录日志(并且可以是更大事务的一部分，将回滚等)。如果您在开发中有不想在表中使用的数据，通常最好截断，因为您不会冒填满事务日志的风险

Truncate命令用于重新初始化表，它是一个删除表中所有行的DDL命令。DELETE是一个DML命令，用于根据某些条件删除一行或一组行，如果没有指定condition，则该命令将删除表中的所有行。