MySQL Select Queries - Cql Typing CST Test
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MySQL Select Queries — Cql Code
Basic MySQL queries for selecting rows with filters and sorting.
-- Select all rows
SELECT * FROM employees;
-- Select with condition
SELECT name, salary FROM employees WHERE salary > 50000;
-- Sort results
SELECT * FROM employees ORDER BY hire_date DESC;Cql Language Guide
Cassandra Query Language (CQL) is the native query language for Apache Cassandra, a highly scalable, distributed NoSQL database. CQL provides a SQL-like syntax for interacting with Cassandra's column-family data model, supporting data definition, manipulation, and retrieval.
Primary Use Cases
- ▸High-volume data ingestion
- ▸Time-series and IoT data management
- ▸Real-time analytics and reporting
- ▸Distributed and fault-tolerant applications
- ▸Data warehousing for large-scale datasets
- ▸Session and user activity tracking
Notable Features
- ▸SQL-like syntax familiar to relational users
- ▸Supports primary keys, clustering columns, and partitioning
- ▸TTL (Time to Live) for automatic data expiration
- ▸Lightweight transactions (LWT) for conditional updates
- ▸Integration with many programming language drivers
- ▸High write and read scalability across clusters
Origin & Creator
CQL was developed by DataStax and the Apache Cassandra community, evolving from 2008 onwards to provide a familiar query interface for Cassandra's wide-column store architecture.
Industrial Note
CQL is critical in industries requiring high availability and write scalability, such as IoT platforms, financial transaction systems, social media feeds, and real-time analytics. Its denormalized, column-family approach allows Cassandra to scale horizontally across multiple nodes.