【转】把一个表的数据插入到另一个表:INSERT INTO SELECT / SELECT INTO

原文链接：http://www.it118.org/Specials/c9fba99e-4401-49cf-8256-ac3c1a34c0d9/cf2a7ceb-1815-43fe-8810-47af11ac65a9.htm

有两种方法可以是实现,而且不使用游标.下面两种方法性能远好于游标.

1.INSERT INTO SELECT
这种方法常用在目标表已经存在数据库中.需要从源表把数据插入到目标表的情况.如果目标表和源表的列相同,就不必列出数据列了.

USE AdventureWorks 
GO 
----Create TestTable 
CREATE TABLE TestTable (FirstName VARCHAR(100), LastName VARCHAR(100)) 
----INSERT INTO TestTable using SELECT 
INSERT INTO TestTable (FirstName, LastName) 
SELECT FirstName, LastName 
FROM Person.Contact 
WHERE EmailPromotion = 2 
----Verify that Data in TestTable 
SELECT FirstName, LastName 
FROM TestTable 
----Clean Up Database 
DROP TABLE TestTable 
GO 
USE AdventureWorks 
GO 
----Create TestTable 
CREATE TABLE TestTable (FirstName VARCHAR(100), LastName VARCHAR(100)) 
----INSERT INTO TestTable using SELECT 
INSERT INTO TestTable --(FirstName, LastName) 
SELECT FirstName, LastName 
FROM Person.Contact 
WHERE EmailPromotion = 2 
----Verify that Data in TestTable 
SELECT FirstName, LastName 
FROM TestTable 
----Clean Up Database 
DROP TABLE TestTable 
GO 

仔细看看有什么区别.

2.SELECT INTO
这种方法用在目标表事先不存在于数据库.在插入数据的同时新建表.新表的字段名和数据类型和需要插入的列相同.

USE AdventureWorks 
GO 
----Create new table and insert into table using SELECT INSERT 
SELECT FirstName, LastName 
INTO TestTable 
FROM Person.Contact 
WHERE EmailPromotion = 2 
----Verify that Data in TestTable 
SELECT FirstName, LastName 
FROM TestTable 
----Clean Up Database 
DROP TABLE TestTable 
GO 

我也常用它来复制数据结构,但不插入数据.

USE AdventureWorks 
GO 
----Create new table and insert into table using SELECT INSERT 
SELECT FirstName, LastName 
INTO TestTable 
FROM Person.Contact 
WHERE 1=2 
DROP TABLE TestTable 
GO