What could be the reason for an "Expression evaluation error: Syntax error" message?

An "Expression evaluation error: Syntax error" message typically signifies that there is an issue with the syntax of the expression used in the code. One of the most common syntax errors occurs when a required punctuation mark, such as a comma, is missing. In Appian, commas are crucial for separating parameters in functions or lists, and their absence can lead to confusion in how the expression is parsed.

When the engine encounters a situation where it's expecting to see a comma but does not find one, it cannot properly interpret the structure of the expression, resulting in a syntax error. This type of error is distinct from logical or evaluation errors, as it specifically pertains to how the expression is written rather than the data being utilized or the structure of the database.

While other choices mention missing parameters, database issues, or lack of data, these scenarios do not specifically cause a "syntax error" but may lead to different types of runtime errors. Therefore, the nature of the syntax error directly relates to issues with the construction of the expression itself, making the absence of a comma the most likely reason for this error message.