CQL DML: SELECT statement

In this lesson, we will focus on the Data Manipulation Language (DML) SELECT operation supported by Apache Cassandra.

The SELECT statement

The SELECT statement is used to retrieve data from one or more columns for one or more rows in a table. Unlike relational databases, Cassandra does not support table joins, and the FROM clause must target a single table only.

A SELECT query without a WHERE clause is supported but is not recommended. Such a query negatively impacts performance as it fetches data distributed around the cluster. Tables in Cassandra are modeled around SELECT queries with the aim of targeting a single partition (thus a single node).