The role of order by in sql

The ORDER BY clause in SQL sorts the rows in the result set to display the data in a specific order. It sorts one or more columns in ascending or descending order, and supports advanced usage such as multi-column sorting, null value handling, and more.

The role of ORDER BY in SQL

In SQL, the ORDER BY clause is used to compare the results in the result set. Rows are sorted. It allows you to sort your data in ascending or descending order based on one or more columns.

Main functions:

• #Organize the result set:Sort the rows returned from the query to display the data in a specific order .
• Group by specific columns: Group rows into a set of columns with the same value before sorting each group.

Syntax:

<code>SELECT ...
FROM ...
WHERE ...
ORDER BY column_name1 [ASC | DESC], column_name2 [ASC | DESC], ...;</code>

• column_name: The name of the column to be sorted.
• ASC: Sort in ascending order (smallest to largest).
• DESC: Sort in descending order (largest to smallest).

Example:

Let us consider a table containing people information:

<code>CREATE TABLE persons (
  id INT PRIMARY KEY,
  name VARCHAR(255),
  age INT
);</code>

To sort the people in the table in ascending order by name, We can use the following query:

<code>SELECT *
FROM persons
ORDER BY name ASC;</code>

This will return rows sorted by name from A to Z.

Advanced usage:

The ORDER BY clause also supports some advanced usage:

• Multiple column sorting: Sort multiple columns at once, such as ascending name and descending age.
• Null value processing: Specify whether the null value is ranked first or last.
• NULLS FIRST/LAST: Sort NULL values ​​to the front or last of the result set.

By using the ORDER BY clause, you can organize and arrange your data efficiently, simplifying query and report generation.

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