The error message 'Variable is not defined' can be caused by using the ampersand character (&) inside a statement.

• A. Unknown
• B. True
• C. False
• D. Not applicable

Answer: (B)

Substitution variables and how the ampersand is treated in SQL clients. In many SQL environments, the ampersand marks a placeholder for a value to be substituted at run time. When a statement includes an &-prefixed variable, the client prompts you for a value or attempts to substitute one. If that variable hasn’t been defined in the current session, the client reports an error like “Variable is not defined.” Snowflake itself doesn’t use & in its SQL syntax, but many GUI tools and command-line clients used with Snowflake support this substitution behavior. So placing an ampersand in a statement can lead to that exact error when the variable isn’t defined, which is why this statement is true.