Boolean columns hold TRUE or FALSE

Some columns hold a plain yes or no — has_library_card, is_active. SQL calls this a boolean column, which means its value is TRUE or FALSE (or NULL if unknown). You compare it to TRUE or FALSE directly, with no quotes, because it isn't text. SQL Server has no TRUE keyword; it stores yes/no as a BIT column holding 1 or 0.

SELECT name
FROM students
WHERE has_library_card = TRUE;