SQL TOP Clause

The TOP clause is used to specify the number of records to return.
The TOP clause can be very useful on large tables with thousands of records. Returning a large number of records can impact on performance.
Note: Not all database systems support the TOP clause.
SQL Server Syntax

SELECT TOP number|percent column_name(s) FROM table_name

 

SQL TOP Example

“Persons” TABLE:

P_Id	LastName	FirstName	Address	City
1	Suhail	Osmani	Maharaj Nagar	Sitapur
2	Maxwel	Tom	Biswan	Sitapur
3	Rahi	Ayon	Okhla	Delhi
4	Nyla	Tom	Rohini	Delhi

Now we want to select only the two first records in the table above.
We use the following SELECT statement:

SELECT TOP 2 * FROM Persons

Output:

P_Id	LastName	FirstName	Address	City
1	Suhail	Osmani	Maharaj Nagar	Sitapur
2	Maxwel	Tom	Biswan	Sitapur

 

SQL TOP PERCENT Example

“Persons” TABLE:

P_Id	LastName	FirstName	Address	City
1	Suhail	Osmani	Maharaj Nagar	Sitapur
2	Maxwel	Tom	Biswan	Sitapur
3	Rahi	Ayon	Okhla	Delhi
4	Nyla	Tom	Rohini	Delhi

Now we want to select only 50% of the records in the table above.We use the following SELECT statement:

SELECT TOP 50 PERCENT * FROM Persons

Output:

P_Id	LastName	FirstName	Address	City
1	Suhail	Osmani	Maharaj Nagar	Sitapur
2	Maxwel	Tom	Biswan	Sitapur