Great! In the previous instruction, we indexed an expression like this:

CREATE INDEX company_insensitive
ON dev_award (LOWER(company));

This index will only be used in queries where the function call LOWER(company) appears, for example:

SELECT
  first_name,
  last_name
FROM dev_award
WHERE LOWER(company) = 'vertabelo';

The index won't be used in the following situation:

SELECT
  first_name,
  last_name
FROM dev_award
WHERE company = 'Vertabelo';

In this case, you'd have to create a separate index on the column company without the LOWER() function.