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SQL - TOP, LIMIT or ROWNUM Clause

The SQL TOP clause is used to fetch a TOP N number or X percent records from a table.
Note: All the databases do not support TOP clause. For example MySQL supports LIMITclause to fetch limited number of records and Oracle uses ROWNUM to fetch limited number of records.

Syntax:

The basic syntax of TOP clause with SELECT statement would be as follows:
SELECT TOP number|percent column_name(s)
FROM table_name
WHERE [condition]

Example:

Consider the CUSTOMERS table having the following records:
+----+----------+-----+-----------+----------+
| ID | NAME     | AGE | ADDRESS   | SALARY   |
+----+----------+-----+-----------+----------+
|  1 | Ramesh   |  32 | Ahmedabad |  2000.00 |
|  2 | Khilan   |  25 | Delhi     |  1500.00 |
|  3 | kaushik  |  23 | Kota      |  2000.00 |
|  4 | Chaitali |  25 | Mumbai    |  6500.00 |
|  5 | Hardik   |  27 | Bhopal    |  8500.00 |
|  6 | Komal    |  22 | MP        |  4500.00 |
|  7 | Muffy    |  24 | Indore    | 10000.00 |
+----+----------+-----+-----------+----------+
Following is an example on SQL server, which would fetch top 3 records from CUSTOMERS table:
SQL> SELECT TOP 3 * FROM CUSTOMERS;
This would produce the following result:
+----+---------+-----+-----------+---------+
| ID | NAME    | AGE | ADDRESS   | SALARY  |
+----+---------+-----+-----------+---------+
|  1 | Ramesh  |  32 | Ahmedabad | 2000.00 |
|  2 | Khilan  |  25 | Delhi     | 1500.00 |
|  3 | kaushik |  23 | Kota      | 2000.00 |
+----+---------+-----+-----------+---------+
If you are using MySQL server, then here is an equivalent example:
SQL> SELECT * FROM CUSTOMERS
LIMIT 3;
This would produce the following result:
+----+---------+-----+-----------+---------+
| ID | NAME    | AGE | ADDRESS   | SALARY  |
+----+---------+-----+-----------+---------+
|  1 | Ramesh  |  32 | Ahmedabad | 2000.00 |
|  2 | Khilan  |  25 | Delhi     | 1500.00 |
|  3 | kaushik |  23 | Kota      | 2000.00 |
+----+---------+-----+-----------+---------+
If you are using Oracle server, then here is an equivalent example:
SQL> SELECT * FROM CUSTOMERS
WHERE ROWNUM <= 3;
This would produce the following result:
+----+---------+-----+-----------+---------+
| ID | NAME    | AGE | ADDRESS   | SALARY  |
+----+---------+-----+-----------+---------+
|  1 | Ramesh  |  32 | Ahmedabad | 2000.00 |
|  2 | Khilan  |  25 | Delhi     | 1500.00 |
|  3 | kaushik |  23 | Kota      | 2000.00 |
+----+---------+-----+-----------+---------+