From first glance, this subquery looks absolutely legit. Unfortunately, it won’t work as a subquery but will work as a standalone query. This is why many students failed this question on the exam. The syntax checker doesn’t accept the ORDER BY in the subquery and complaints about missing of the closing parenthesis. And it is easy to verify – just move ORDER BY from subquery to main query and everything will work. This thing worth to be remembered.
If you have a table with existing data ( as shown below) and you’ve been asked to add a NOT NULL column […]
The LISTAGG analytic function was not covered in Roopesh Ramklass book, but it is part of the exam. It makes it very easy to aggregate […]
It does not make any sense to sort data before passing them to an outer query from inner query. The subquery will be […]
There are some questions on the exam to verify your knowledge about finding the second highest value of the table or column. […]
