SQL Anywhere® Server - Database Administration  > Database Options  > Introduction to database options  > Alphabetical list of options

tsql_variables option [compatibility]

Controls whether the @ sign can be used as a prefix for embedded SQL host variable names.

On, Off

Off

On for Open Client and jConnect connections

When this option is set to On, you can use the @ sign instead of the colon as a prefix for host variable names in embedded SQL. This is implemented primarily for Transact-SQL compatibility.