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Databases

Posted by renhe
renhe
10,282 Points

Longest Name

For the first practice query in playground, is there a way to order by an alias name? If I give LENGTH(name) an alias such as 'Name Length', is there a way I can order by 'Name Length' or would I have to order by LENGTH(name)?

1 Answer

Steven Parker
Steven Parker
231,248 Points
Steven Parker
Steven Parker
231,248 Points

Either should work.

You should be able to ORDER BY the alias just as easily as by the term that produces the column.

renhe
renhe
10,282 Points

The following query: SELECT name, LENGTH(name) AS 'Name Length' FROM actors ORDER BY 'Name Length' DESC LIMIT 1; returns name: 'Chico' Hernandez, Name Length: 17

But this one: SELECT name, LENGTH(name) AS 'Name Length' FROM actors ORDER BY LENGTH(name) DESC LIMIT 1; returns name: The Hallelujah Singers of Beaufort South Carolina, Name Length: 49

And if I don't have Name Length in quotes I get this error - Error: near "Length": syntax error

Steven Parker
Steven Parker
231,248 Points
Steven Parker
Steven Parker
231,248 Points

Yes, any name that has spaces in it must be enclosed in quotes.

As for the deviation in the results, can you provide a link to a course page where I could try your examples in the playground or challenge?

renhe
renhe
10,282 Points

Thanks for the help Steven!

Here's the link: https://teamtreehouse.com/sql_playgrounds/372#/queries/df235db9-f3a0-4116-b649-802e66f34021?_k=gqewiv

Steven Parker
Steven Parker
231,248 Points
Steven Parker
Steven Parker
231,248 Points

Ahh. That was the wrong kind of quote for a column name. What you need there is:

SELECT name, LENGTH(name) AS "Name Length" FROM actors ORDER BY "Name Length" DESC LIMIT 1;

Remember: single quotes (') are for strings, double quotes (") are for column names.