SQL is a pervasive querying language. While there is one primary SQL dialect that all SQL RDBMS implementations must support, and that's ANSI SQL, each database platform comes out with its own context. Each of these dialects has its own DDL (Data Definition Language). DML (Data Manipulation Language). and DQL (Data Query Language). Other than for marketing purposes (to sell the product as unique), what is the value of creating a new variation of a SQL dialect. 

Provide an example of one SQL dialect as part of your write-up.