What is the difference between SQL and relational algebra?

Question

Relational algebra is a useful theoretical language that serves to define more complex languages. The second language we consider, Structured Query Language or SQL, is a practical language that allows a high-level expression of queries.

Relational Algebra is procedural query language, which takes Relation as input and generate relation as output. Relational algebra mainly provides theoretical foundation for relational databases and SQL.

What is the difference between SQL and relational databases?

SQL databases are known as relational databases, and have a table-based data structure, with a strict, predefined schema required. NoSQL databases, or non-relational databases, can be document based, graph databases, key-value pairs, or wide-column stores.

Should I learn relational algebra before SQL?

You don't need to know jack about relational algebra or set theory or anything to intuitively understand SQL and how to construct a set of tables.

Is SQL more powerful than relational algebra?

The conclusion, of course, is that SQL has more power than relational alge- bra, and the main source of this additional power is its aggregation and grouping constructs, together with arithmetic operations on numerical attributes.

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