Welcome to the Treehouse Community
Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.
Looking to learn something new?
Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.Start your free trial
I don't get this. Are there any documentation that helps explain this further?
I don't understand the difference between string literals and column aliases, and why those two has to be identified using different type of quotes? Are there other cases where different quotes has to be used?
Steven Parker228,991 Points
For the most part, you will use single quotes with SQL. Double quotes are rarely needed, and generally only when a column name (either an actual column or an alias) contains some unusual character like a space or symbol. The key to remember is single is for string, and double is for identifier.
The SQLite database used in the courses is more flexible that most, as it will allow the use of single or double quotes for both identifiers and strings. But it's good to get in the habit of using them in the "official" way so you can work with other databases easily later.
kevin hudsonCourses Plus Student 11,987 Points
So in simple terms - if you need to concatenate a string with a column then use single quotes - if you are alias a column then use double quote marks.