Temp Table VS Table Variable in SQL Server

Here are some differences between Temp Table and Table Variable in SQL Server

Temp Table Table Variable
Temp table is valid for a session.

For eg: when you run the following code

create table #temp(i int)
insert into #temp select 345
Go
create table #temp(i int)
insert into #temp select 345
Go

you will get an error Table variable has a statement-level scope. ie as soon as you execute the statement the scope is lost

For eg: when you run the following code

declare @t table(i int)
insert into @t select 45
GO
declare @t table(i int)
insert into @t select 45
GO

you will not get an error
It is possible to alter the temp table to add columns, idexes,etc It is not possible to alter a table variable
It is possible to truncate a temp table It is not possible to truncate a table variable
SELECT INTO method can be used for temp table


SELECT * INTO #temp from your_table
SELECT INTO method cannot be used for table variable. You get error for the following

SELECT * INTO @t from your_table
Temp table can be useful when you have a large amount of data For small set of data, table variables can be useful