我們有兩種方式刪除數(shù)據(jù)，DELETE語句和TRUNCATE語句。需要注意它們的區(qū)別，DELETE語句是以完整模式記錄日志的，所以它的性能相對(duì)較低。而TRUNCATE語句是以最小模式來記錄日志的，并且它會(huì)重置標(biāo)識(shí)種子。下面是示例代碼。

USE tempdb;GO-- 準(zhǔn)備測(cè)試數(shù)據(jù)IF OBJECT_ID('dbo.Orders','U') IS NOT NULL DROP TABLE dbo.Orders;IF OBJECT_ID('dbo.Customers','U') IS NOT NULL DROP TABLE dbo.Customers;GOSELECT * INTO dbo.Orders FROM TSQLFundamentals2008.Sales.Orders;SELECT * INTO dbo.Customers FROM TSQLFundamentals2008.Sales.Customers;ALTER TABLE dbo.Customers ADDCONSTRAINT PK_Customers PRIMARY KEY(custid);ALTER TABLE dbo.Orders ADDCONSTRAINT PK_Orders PRIMARY KEY(orderid),CONSTRAINT FK_Orders_Customers FOREIGN KEY(custid) REFERENCES dbo.Customers(custid);-- 刪除數(shù)據(jù)-- 方法一：DELETE(完整模式日志,性能低)DELETE FROM dbo.OrdersWHERE orderdate<'20070101';-- 基于聯(lián)接的DELETEDELETE FROM orders FROM dbo.Orders AS ordersLEFT JOIN dbo.Customers AS customers ON orders.custid= customers.custidWHERE customers.country= N'USA';-- 方法三：TRUNCATE(最小模式日志,性能高；重置標(biāo)識(shí)種子)TRUNCATE TABLE dbo.Orders;