What is temporary table in sql server

Q. What are temporary tables? when to use them?

Ans. Temporary tables are used to store any data on a temporary basis. in Tempdb.

used to perform data calculations, data formatting operations for reporting.

create table #table1

(

col1 int,

col2 int,

col3 int

)  -- Local temporary table

insert into #table1 values (10,10,10), (20,20,20)

select * from #table1

Local temp tables:- Local temp tables are auto removed from temp-db once you close the session.and local temp tables are represent by single # symbol.

-session means this query windows

create table ##table1

(

 col1 int,

 col2 int,

 col3 int

)  -- global temporary table

insert into ##table1 values (10,10,10), (20,20,20)

select * from ##table1

Global temp tables:- global temp tables are auto removed from temp-db once you close the connection.and global temp tables are represent by ## symbol.

connection means server level authenticated entry to the database.

             

ssms >> server name >> connect close ssms: connection close

for better reuse: permenant tables are recommended.

for faster performance: temp tables are recommended.