Using TOP keyword
The TOP clause used with the SELECT statement. It is used to limits the number of rows returned in the result set
SELECT [TOP n] column_mame FROM table_name WHERE search_conditions
'n'=number of rows that you want to retrieve.
SELECT TOP 5 pub_id,pub_name,country FROM publishers WHERE country LIKE 'U%' ORDER BY pub_id DESC
Returns all top 5 rows ,pub_id, pub_name and country,& from the publishers table in descending order & with respect to pub_id.
Using DISTINCT keyword
It also used to limit the result set. The DISTINCT keyword remove the duplicate row from the returned result set. It used with the SELECT statement.
SELECT DISTINCTcolumn_mame FROM table_name WHERE search_conditions
SELECT DISTINCT country FROM publishers WHERE city LIKE 'B%'
Return country name which started with a 'B' alphabet but no repetition, means no duplicate value of country.