{code:sql} in Jira recognizes -- comment but not /* comment */, which is supported by the Transact-SQL (T-SQL) language in Microsoft SQL Server. Please add syntax highlighting for that, too. It could be part of {code:sql} or have a distinct language identifier such as {code:mssql} or {code:t-sql}.

SELECT
  number_of_protons /* comment */,
  relative_atomic_mass -- comment
FROM elements;

According to the Microsoft documentation for Slash Star (Block Comment) (Transact-SQL), comments of this type can nest.