Here’s a quick overview of the difference between SQL and T-SQL (Transact-SQL). Not so much the differences as such, but more an explanation of T-SQL and where it sits in relation to SQL.
If you’ve done any database development or administration, you’re probably familiar with SQL. SQL, which stands for Structured Query Language, is a standard query language for working with databases. Most of the major relational database management systems such as MySQL, Oracle, SQL Server, PostgreSQL, etc support SQL in one way or another.
However, while the SQL standard provides clear specifications, it also allows for database vendors to add their own extensions. This allows vendors to provide extra features and functionality for their customers that might not be offered by their competitors.
This is where T-SQL comes in.