Strings can only be joined with which of the following?

Strings can only be joined with string fields because concatenation, which is the process of joining strings together, requires that both elements involved in the operation are of the same type. In this case, when you combine two strings, you’re effectively creating a new string that represents the combined value of the two. Each type of field, such as numeric, date/time, or logical, requires different operations or handling and cannot be directly concatenated to a string without converting them into a string format first. This characteristic ensures data type integrity and proper functioning within processing and analysis tasks in Alteryx. For example, joining a numeric value directly with a string would not yield the desired result without first converting the numeric value to a string format, which is a separate operation.