2015. 6. 7. 22:17
http://www.w3schools.com
The SQL SELECT TOP Clause
The SELECT TOP clause is used to specify the number of records to return.
The SELECT 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 SELECT TOP clause.
SQL Server / MS Access 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 5;
FROM Persons
LIMIT 5;
Oracle Syntax
SELECT column_name(s)
FROM table_name
WHERE ROWNUM <= number;
FROM table_name
WHERE ROWNUM <= number;
Example
SELECT *
FROM Persons
WHERE ROWNUM <=5;
FROM Persons
WHERE ROWNUM <=5;
SQL SELECT TOP Example
The following SQL statement selects the two first records from the "Customers" table:
SQL SELECT TOP PERCENT Example
The following SQL statement selects the first 50% of the records from the "Customers" table: