The SQL ORDER BY clause is used to sort the result set of a SELECT statement in a specified order. It allows you to sort the rows returned by a query based on one or more columns. The syntax for the ORDER BY clause is:
SELECT column1, column2, ... FROM table_name ORDER BY column1 [ASC|DESC], column2 [ASC|DESC], ...;
In this syntax, column1, column2, etc. are the columns that you want to sort the result set by, and ASC or DESC specifies the sort order.
By default, the ORDER BY clause sorts the result set in ascending order. If you want to sort the result set in descending order, you can use the DESC keyword.
For example, let’s say you have a table called “customers” with columns “customer_id”, “first_name”, and “last_name”. You can sort the result set by the “last_name” column in ascending order like this:
SELECT * FROM customers ORDER BY last_name;
If you want to sort the result set in descending order, you can add the DESC keyword like this:
SELECT * FROM customers ORDER BY last_name DESC;
You can also sort the result set by multiple columns. For example, you can sort the “customers” table by “last_name” in ascending order and “first_name” in descending order like this:
SELECT * FROM customers ORDER BY last_name, first_name DESC;
In summary, the SQL ORDER BY clause is a powerful tool that allows you to sort the result set of a SELECT statement in a specified order. It can be used to sort the result set by one or more columns in ascending or descending order.