SQL Standard-Style Comments

In Transact-SQL, comments are delimited by “/*” and “*/”, and can be nested. Transact-SQL also supports SQL standard-style comments, which consist of any string beginning with two connected minus signs, a comment, and a terminating new line.

select "hello" -- this is a comment

The Transact-SQL “/*” and “*/” comment delimiters are fully supported, but “--” within Transact-SQL comments is not recognized.