Why is this an issue?
When multiple tables are involved in a query, using table aliases helps to make it more understandable and keeps it short.
Noncompliant code example
FROM employee -- Noncompliant - should be aliased
INNER JOIN department -- Noncompliant - should be aliased
ON employee.DepartmentID = department.ID;
FROM employee empl
INNER JOIN department dpt
ON empl.DepartmentID = dpt.ID;