Cassandra Filtering & Sorting Data

In Cassandra, filtering and sorting data is performed using the CQL (Cassandra Query Language) which supports a wide range of filtering and sorting operations.

Filtering Data in Cassandra:

The WHERE clause in CQL is used for filtering data in Cassandra. The WHERE clause is used in a SELECT statement to filter the data based on one or more conditions. The basic syntax for filtering data is as follows:

SELECT column1, column2, ..., columnN
FROM table_name
WHERE condition;

In the above syntax, column1, column2, …, columnN represents the columns in the table that you want to retrieve. table_name represents the name of the table from which you want to retrieve data. The WHERE clause is used to filter the data based on a condition.

Example:

Let’s say we have a table named users with the following columns: id, name, email, and age. We want to retrieve all the users whose age is greater than 30. The query for this would be:

SELECT id, name, email, age
FROM users
WHERE age > 30;

Sorting Data in Cassandra:

CQL supports sorting data using the ORDER BY clause. The ORDER BY clause is used in a SELECT statement to sort the data based on one or more columns. The basic syntax for sorting data is as follows:

SELECT column1, column2, ..., columnN
FROM table_name
ORDER BY column_name ASC|DESC;

In the above syntax, column1, column2, …, columnN represents the columns in the table that you want to retrieve. table_name represents the name of the table from which you want to retrieve data. The ORDER BY clause is used to sort the data based on the specified column name in either ascending (ASC) or descending (DESC) order.

Example:

Let’s say we have a table named products with the following columns: id, name, description, price. We want to retrieve all the products sorted by their price in descending order. The query for this would be:

SELECT id, name, description, price
FROM products
ORDER BY price DESC;

Filtering and Sorting Data Together:

CQL also supports filtering and sorting data together. You can use the WHERE and ORDER BY clauses together in a SELECT statement to filter and sort data based on one or more columns. The basic syntax for filtering and sorting data together is as follows:

SELECT column1, column2, ..., columnN
FROM table_name
WHERE condition
ORDER BY column_name ASC|DESC;

In the above syntax, column1, column2, …, columnN represents the columns in the table that you want to retrieve. table_name represents the name of the table from which you want to retrieve data. The WHERE clause is used to filter the data based on the specified condition and the ORDER BY clause is used to sort the data based on the specified column name in either ascending (ASC) or descending (DESC) order.

Example:

Let’s say we have a table named orders with the following columns: order_id, customer_id, product_id, quantity, and order_date. We want to retrieve all the orders for a particular customer (customer_id = 123) and sort them by order_date in descending order. The query for this would be:

SELECT order_id, customer_id, product_id, quantity, order_date
FROM orders
WHERE customer_id = 123
ORDER BY order_date DESC;