CONCAT function requires exactly two arguments

CONCAT function requires exactly two arguments and it seems obvious. But, when you encounter some complex SQL queries like one below, you can easily forget about this rule and make mistake during the test.

 

As we can see, || operator turned two SUBSTR results into one, therefore CONCAT received only one argument.

Tricks like that are difficult to catch from the first glance, but they are happening on the exam all the time.

 

Leave a comment

Your email address will not be published. Required fields are marked *