Statement 1 (No): The query uses the OUTER APPLY operator, which is designed to invoke a Table-Valued Function (TVF) for each row of the outer table. The usage gdr.[WWI Employee ID] in the SELECT clause confirms that the function returns a table structure with columns, not a single scalar value.

Statement 2 (No): The APPLY operator functions conceptually like a "correlated join." It executes the table-valued function for each row returned by the outer table expression (Dimension.Employee), passing the current row's [Employee Key] as a parameter. It does not run just once.

Statement 3 (Yes): OUTER APPLY behaves similarly to a LEFT OUTER JOIN. It returns all rows from the left-side table (Dimension.Employee) regardless of whether the function returns any rows. If the function returns an empty set for a specific employee, the query still returns that employee's row with NULL values for the gdr columns.

Microsoft Learn. (2023). FROM clause plus JOIN, APPLY, PIVOT (Transact-SQL). Retrieved from https://learn.microsoft.com/en-us/sql/t-sql/queries/from-transact-sql

Relevant Quote: "The APPLY operator allows you to invoke a table-valued function for each row returned by an outer table expression of a query."

Relevant Quote: "OUTER APPLY returns both rows that produce a result set, and rows that do not, with NULL values in the columns produced by the table-valued function."

Microsoft Learn. (2023). Create User-defined Functions (Database Engine). Retrieved from https://learn.microsoft.com/en-us/sql/relational-databases/user-defined-functions/create-user-defined-functions-database-engine

Context: Defines the distinction between Scalar and Table-Valued functions and their usage in FROM clauses.