SQL TOP Clause

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The 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 SELECT TOP Equivalent in MySQL and Oracle

MySQL Syntax

SELECT column_name(s)
FROM table_name
LIMIT number

Example

SELECT !!
FROM Persons
LIMIT 5

Oracle Syntax

SELECT column_name(s)
FROM table_name
WHERE ROWNUM <= number

Example

SELECT !!
FROM Persons
WHERE ROWNUM <=5

SQL TOP Example

The "Persons" table:

P_Id LastName FirstName Address City
1 Karmen Kasa Los Angels - USA New Orleans
2 Jacob Mary Los Angels - USA New Orleans
3 Maxwell Glen Australia Sydney
4 Tendulkar Sachin India Mumbai

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

The result-set will look like this:

P_Id LastName FirstName Address City
1 Karmen Kasa Los Angels - USA New Orleans
2 Jacob Mary Los Angels - USA New Orleans

SQL TOP PERCENT Example

The "Persons" table:

P_Id LastName FirstName Address City
1 Karmen Kasa Los Angels - USA New Orleans
2 Jacob Mary Los Angels - USA New Orleans
3 Maxwell Glen Australia Sydney
4 Tendulkar Sachin India Mumbai

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

The result-set will look like this:

P_Id LastName FirstName Address City
1 Karmen Kasa Los Angels - USA New Orleans
2 Jacob Mary Los Angels - USA New Orleans

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