Why doesn't the SELECT statement within a FUNCTION work in MariaDB when selecting a table?

edit

The SELECT statement within a FUNCTION in MariaDB may not work when selecting a table because table-level operations are not allowed in a function. Functions are designed to return a single value, and table-level operations may return multiple rows and columns, which can cause issues with the function's behavior. To perform table-level operations, use a stored procedure instead of a function.