Table variables in SQL Server

Microsoft introduced table variables in SQL Server, table variable is used instant of Temporary Tables.

In Table variables we can store our records; the declaration of syntax is very similar to a CREATE TABLE statement.

Example:
Declare @customersvar Table(
Id int identity(1,1),
customerID nchar(5) NOTNULL,
Name varchar(50) ,
Address varchar(max) ,
PhoneNo varchar(50) )

We can write the following INSERT INTO statement to insert values in the table variable.

Insert into @customervar Table (customerID, Name, Address, PhoneNo )

Select customerID, Name, Address, PhoneNo from Customers

We can write the following SELECT statement to populate the table variable.

Select * from @customersvar

And to populate the table variables first fifty values, you can write the following SELECT statement

Select top 50 * from @customersvar

When we create a temporary table (#TABLE) , which physically creates the table in tempdb so it is creates burden . When we create a table variable which is creating in memory so it's much faster.

And we can use table variables when creating batches, stored procedures, and user-defined functions (UDFs).

And also you can UPDATE records in your table variable as well as DELETE records.

Example:
UPDATE @customersvar SET Name = ‘Reema’ WHERE customerID = 158

DELETE FROM @customersvar WHERE customerID = 1020