For SQL, in my previous blog, what is an SQL Server database? What is the difference with access database? It has already highlighted SQL as the standard computer language for accessing and processing databases, so I will not emphasize it too much here. Let's talk about T-SQL.
As an extension language of SQL, T-SQL is an enhanced version of SQL programming language. It is the main language for applications to communicate with SQL Server. The T-SQL provides DDL and DML functionality for standard SQL, along with extended functions, system pre-stored programs, and programming structures (such as if and while) to make continued design more flexible. Here I will explain what "The T-SQL provides standard SQL DDL and DML functionality" means. Relational Database languages are divided into three types: Data Definition Language (DDL), data manipulation language (DML), and data control language (DCL. SQL is a standard relational database language integrating DDL, DML, and DCL. The DDL data definition language is used to define and manage all objects in the SQL database. The DML data manipulation language and SQL statements for data processing are collectively referred to as the data manipulation language.
Finally, let's talk about the origin of T-SQL. The US National Bureau of Standards (ANSI) and the International Organization for Standardization have formulated SQL standards. The US National Bureau of Standards issued the United States standards (which can be understood as convenient for domestic use) corresponding to the International Organization for Standardization ), in 1992, the International Organization for Standardization and International Electrotechnical Commission (IEC) released the SQL international standard known as SQL-92. The corresponding standard published by the US National Bureau of Standards is the ANSI SQL-92. Although different databases use different SQL versions, most of them follow the ansi SQL standard. SQL Server uses an extended set of ANSI SQL-92 called T-SQL.
In a word, SQL, as a structured query language, is a standard language for standard relational databases; T-SQL is a language used in SQL Server Extension Based on SQL.