SQL comments

Let’s say we have a query to get all students whose grade is less than 8.

Suppose we quickly want to check the list of all students without actually deleting the WHERE condition from query.

Like all other programming languages, we can use comments in SQL too to mark part of code not to be run.

Any part of a line starting from -- till the end of line will be considered a comment. Go ahead and run the query below where the entire query is in a single line. Some part of the query is commented out.

We can also use comments to add documentation to our queries.