External functions can be used as part of a complex expression.

• A. True
• B. False
• C. Only in WHERE clauses
• D. Only when used with JSON

Answer: (A)

External functions in Snowflake act as scalar functions, so they can be used anywhere a single value expression is allowed. Because of that, you can weave them into complex expressions just like you would with built-in functions. They can participate in arithmetic, comparisons, and be placed in the SELECT list, in WHERE, HAVING, or other parts of a query, as long as the function returns a scalar value. This enables scenarios like computing a value with an external call and then combining it with other columns, or filtering rows based on the result of that call. It’s not limited to a WHERE clause, and it’s not restricted to JSON usage, which is why those other options don’t fit. Just remember external calls can add latency since they reach out to an external service.