When using coalesce, what is the expected output if all arguments are null?

The function coalesce is designed to return the first non-null argument it encounters. If all the arguments provided to coalesce are null, it has no non-null value to return, and therefore, it results in null.

This is consistent with the expected behavior of coalesce in programming and database systems where it is used to handle null values effectively. By returning null, coalesce allows developers to manage potential null scenarios gracefully in their applications or queries. In contrast, other options such as zero, an empty string, or an error message would not accurately reflect the function's intent, as coalesce specifically operates in the context of nullity.