What is the function of order by in sql

The ORDER BY clause is used to sort the rows in SQL query results by a specified column or expression to organize the results for analysis and reporting. Specific functions include: sorting rows in ascending or descending order, specifying the sort order, processing equal values, and supporting compound sorting.

The role of ORDER BY in SQL

The ORDER BY clause is used to select rows by specified columns or expressions in SQL query results. Sort. It allows you to organize results according to specific criteria for easy data analysis, visualization and reporting.

Function:

The specific functions of the ORDER BY clause include:

• Sort rows:Pair rows by specified column or expression The resulting rows are sorted in descending or ascending order.
• Specify the sort order: Use the ASC (ascending order) or DESC (descending order) keyword to specify the sort order.
• Handling equal values: If multiple rows have the same sort value, ORDER BY can use additional sorting columns or expressions to further sort those rows.
• Support compound sorting: Allows sorting by multiple columns or expressions to create more complex sorting rules.

Usage:

The ORDER BY clause is generally used at the end of the SELECT statement. The syntax is as follows:

<code class="sql">SELECT column_list
FROM table_name
ORDER BY column_name [ASC | DESC], ...;</code>

Among them:

• column_name is the column or expression to be sorted.
• ASC means ascending sorting (from smallest to largest).
• DESC means sorting in descending order (from largest to smallest).

Example:

The following example demonstrates how to use ORDER BY to sort the employee table by name and salary:

<code class="sql">SELECT name, salary
FROM employees
ORDER BY name ASC, salary DESC;</code>

The result will be by name in ascending order and by name in descending order. Employees are ranked by salary.

Note:

• ORDER BY only sorts the query results and does not modify the data in the original table.
• If you want to sort NULL values, you need to use the IS NULL or COALESCE() function.
• ORDER BY can be used in subqueries to sort rows in the final result.

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