Use and difference of insert into select and select into from

1. When to use

These two statements should be used when you need to copy the table.

2. insert into select

Usage: insert into Table2 (field1, field2,...) Select value1, value2,... from Table1

Requirement: The target table Table2 must exist. Because the target table Table2 already exists, in addition to inserting the field of the source table Table1, you can also insert

Input constant.

Instance:

View code

-- 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 ('zhao ', 'asds', '90 ')
Insert into Table1 values ('money', 'asds ', '123 ')
Insert into Table1 values ('sun', 'asds ', '80 ')
Insert into Table1 values ('lil', '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 result
Select * From Table2
Go
-- 5. Delete the test table
Drop table Table1
Drop table Table2

3. Select into from

Usage: Select vale1, value2 into Table2 from Table1

Requirement: The target table 2 does not exist because table 2 is automatically created during insertion and the specified field data in table 1 is copied to table 2.

Instance:

View code

-- 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 ('zhao ', 'asds', '90 ')
Insert into Table1 values ('money', 'asds ', '123 ')
Insert into Table1 values ('sun', 'asds ', '80 ')
Insert into Table1 values ('lil', 'asds ', null)
Go

-- 3. Select into from statement to Create Table 2 and copy data
Select a, c into Table2 from Table1
Go

-- 4. display the updated result
Select * From Table2
Go
-- 5. Delete the test table
Drop table Table1
Drop table Table2