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.
SQL Server Syntax
SELECT TOP number|percent column_name(s)
FROM table_name
FROM table_name
SQL SELECT TOP Equivalent in MySQL and Oracle
MySQL Syntax
SELECT column_name(s)
FROM table_name
LIMIT number
FROM table_name
LIMIT number
Example
SELECT *
FROM Persons
LIMIT 6
FROM Persons
LIMIT 6
Oracle Syntax
SELECT column_name(s)
FROM table_name
WHERE ROWNUM <= number
FROM table_name
WHERE ROWNUM <= number
Example
SELECT *
FROM Persons
WHERE ROWNUM <=6
FROM Persons
WHERE ROWNUM <=6
SQL TOP Example
The "Persons" table:
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
SQL TOP PERCENT Example
The "Persons" table:
We use the following SELECT
statement:
SELECT TOP 50 PERCENT * FROM Persons
The result-set will look like this:
Note: Not all database systems support the TOP clause.
