- 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:
SQL SELECT TOP Equivalent in MySQL and Oracle:
MySQL Syntax:
SELECT column_name(s) FROM table_name LIMIT numberExample:
SELECT * FROM Persons LIMIT 5Oracle Syntax
SELECT column_name(s) FROM table_name WHERE ROWNUM <= numberExample
SELECT * FROM Persons WHERE ROWNUM <=5SQL 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 PersonsThe result-set will look like this:
P_Id LastName FirstName Address City 1 Hansen Ola Timoteivn 10 Sandnes 2 Svendson Tove Borgvn 23 SandnesSQL TOP PERCENT Example
The “Persons” table:
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 PersonsThe result-set will look like this:
