Difference between SELECT INTO and INSERT INTO SELECT two table replication statements

http://my.oschina.net/MiniBu/blog/699086

Insert is a common statement in T-sql, Insert INTO table(field1,field2,...) values(value1,value2,...) in this form Essential in application development. However, in the process of development and testing, we often encounter situations that require table replication, such as copying part of the data of a table1 to table2, or copying the entire table1 to table2. At this time, we will use SELECT INTO and INSERT INTO SELECT table replication statement too.

1. The form of the INSERT INTO SELECT statement

  is:

Insert into Table2(field1,field2,...) select value1,value2,... from Table1

  It is required that the target table Table2 must exist . Since the target table Table2 already exists, we can insert constants in addition to the fields of the source table Table1. An example is as follows:

   --1. Create a test table
    create TABLE Table1
    (
        a varchar(10),
        b varchar(10),
        c varchar(10),
        CONSTRAINT [PK_Table1] PRIMARY KEY CLUSTERED
        (
            a ASC
        )
    ) ON [PRIMARY]

    create TABLE Table2
    (
        a varchar(10),
        c varchar(10),
        d int,
        CONSTRAINT [PK_Table2] PRIMARY KEY CLUSTERED
        (
            a ASC
        )
    ) ON [PRIMARY]
    GO
    --2. Create test data
    Insert into Table1 values('赵','asds','90')
    Insert into Table1 values('钱','asds','100')
    Insert into Table1 values('孙','asds','80')
    Insert into Table1 values('李','asds',null)
    GO
    select * from Table2

    --3.INSERT INTO SELECT statement to copy table data
    Insert into Table2(a, c, d) select a,c,5 from Table1
    GO

    --4. Display the updated results
    select * from Table2
    GO
    --5. Delete the test table
    drop TABLE Table1
    drop TABLE Table2

2. The form of the SELECT INTO FROM statement

  is:

SELECT vale1, value2 into Table2 from Table1

  It is required that the target table Table2 does not exist , because the table Table2 will be automatically created when inserting, and the specified field data in Table1 will be copied to Table2. An example is as follows:

   --1. Create a test table
    create TABLE Table1
    (
        a varchar(10),
        b varchar(10),
        c varchar(10),
        CONSTRAINT [PK_Table1] PRIMARY KEY CLUSTERED
        (
            a ASC
        )
    ) ON [PRIMARY]
    GO

    --2. Create test data
    Insert into Table1 values('赵','asds','90')
    Insert into Table1 values('钱','asds','100')
    Insert into Table1 values('孙','asds','80')
    Insert into Table1 values('李','asds',null)
    GO

    --3.SELECT INTO FROM statement to create table Table2 and copy data
    select a,c INTO Table2 from Table1
    GO

    --4. Display the updated results
    select * from Table2
    GO
    --5. Delete the test table
    drop TABLE Table1
    drop TABLE Table2

Original address: http://www.cnblogs.com/freshman0216/archive/2008/08/15/1268316.html