hive sql order by

In Hive SQL, the `ORDER BY` clause is used to sort the result set of a query based on one or more columns. The `ORDER BY` clause can be used with both single-column and multi-column sorting.

Here's the basic syntax for using `ORDER BY` in Hive:

SELECT column1, column2, ...
FROM table_name
ORDER BY column1 [ASC|DESC], column2 [ASC|DESC], ...

In the above syntax, `column1`, `column2`, etc. represent the columns you want to sort the result set by. You can specify multiple columns separated by commas to perform a multi-column sort.

The optional `ASC` (ascending) or `DESC` (descending) keyword can be used to specify the sort order for each column. By default, if no sort order is specified, it will be sorted in ascending order.

Here's an example to illustrate how to use `ORDER BY` in Hive:

SELECT name, age, salary
FROM employees
ORDER BY age DESC, salary ASC;

In the above example, the result set will be sorted first by the `age` column in descending order, and then by the `salary` column in ascending order.

It's important to note that when using `ORDER BY` in Hive, the entire result set is loaded into memory for sorting. If dealing with large datasets, you may want to consider using other techniques like distributed sorting or bucketing for better performance.