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SQL Select Top

SQL Select Top is a command used to retrieve a specific number of rows from a table. It is commonly used to retrieve the top or highest values from a table based on a certain criteria. The SELECT TOP statement is supported by most relational database management systems (RDBMS) such as MySQL, Oracle, and Microsoft SQL Server.

The SELECT TOP statement is used in conjunction with the SELECT statement to retrieve a specific number of rows from a table. The syntax for the SELECT TOP statement is as follows:

SELECT TOP number|percent column_name(s)
FROM table_name
WHERE condition;

The number parameter specifies the number of rows to be retrieved, while the percent parameter specifies the percentage of rows to be retrieved. The column_name(s) parameter specifies the columns to be retrieved, and the table_name parameter specifies the table from which the rows are to be retrieved. The condition parameter specifies the condition that must be met for the rows to be retrieved.

Here are some examples of how the SELECT TOP statement can be used:

Example 1: Retrieve the top 5 rows from a table

SELECT TOP 5 *
FROM customers;

This statement retrieves the top 5 rows from the customers table.

Example 2: Retrieve the top 10% of rows from a table

SELECT TOP 10 PERCENT *
FROM orders
WHERE order_date >= '2021-01-01';

This statement retrieves the top 10% of rows from the orders table where the order_date is greater than or equal to January 1, 2021.

Example 3: Retrieve the top 3 highest values from a table

SELECT TOP 3 product_name, unit_price
FROM products
ORDER BY unit_price DESC;

This statement retrieves the top 3 highest values from the products table based on the unit_price column.

The SELECT TOP statement is a powerful tool for retrieving specific rows from a table. It can be used to retrieve the top or highest values from a table based on a certain criteria. By using the SELECT TOP statement, you can easily retrieve the data you need from a table without having to retrieve all the data and then filter it manually.

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