Language Elements (Transact-SQL)

**APPLIES TO:** ![yes](media/yes.png)SQL Server (starting with 2008) ![yes](media/yes.png)Azure SQL Database ![yes](media/yes.png)Azure SQL Data Warehouse ![yes](media/yes.png)Parallel Data Warehouse

SQL Server supports the following language elements.

In This Section

– (Comment) (Transact-SQL)

Slash Star (Block Comment) (Transact-SQL)

CREATE DIAGNOSTICS SESSION (Transact-SQL)

NULL and UNKNOWN (Transact-SQL)

Transactions (SQL Data Warehouse)

USE (Transact-SQL)