Commenting - player BMI
Adding comments is a good way to convey what the query is about or information about certain parts of the query.
The sample code is a query on the Players
table that returns player name, country of origin and a calculated Body Mass Index (BMI). The WHERE
condition is filtering for only players from North America.
You will add the following comment.
Returns the Body Mass Index (BMI) for all North American players
from the 2017-2018 NBA season
Also, you believe that ORDER BY
is unnecessary in this query so it will be commented out and a comment added on the same line indicating it is not required.
This exercise is part of the course
Improving Query Performance in SQL Server
Exercise instructions
- Create a comment block on lines 1 and 4.
- Add the above comment to the block.
- Comment out the
ORDER BY
statement and addOrder by not required
comment on the same line. - Add
;
directly after'Canada'
to indicate the new ending of the query.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
SELECT PlayerName, Country,
ROUND(Weight_kg/SQUARE(Height_cm/100),2) BMI
FROM Players
WHERE Country = 'USA'
OR Country = 'Canada'
ORDER BY BMI;