1. Relational vs. non-relational

• SQL databases are relational while NoSQL databases are non-relational.
• A relational database is a digital database based on the relational model of data.
• A non-relational database is not based on the traditional table structure that you may be used to. Instead, it is based on a more flexible model that can be adapted to fit the needs of the application.

2. Data schemas

• SQL databases use a predefined schema and structured query language.
• NoSQL databases have dynamic schemas that can accommodate unstructured data, which is often stored in a variety of ways.

3. Scaling

• SQL databases are known for their ability to scale vertically in most situations.
• It means you can increase the performance by adding more resources like CPU, RAM, or faster hard drives.
• NoSQL databases are able to scale horizontally, meaning they can handle an increased workload by adding more servers.

4. Data structure

• SQL databases store data in tables.
• NoSQL databases are usually a document or key-value stores.

5. Use cases

• SQL databases are the best choice for complex queries. If the data integrity and transactions are the requirements the SQL is better than NoSQL.
• If you're working with constantly changing data structures or JSON data, NoSQL could be a better choice.