Question

Is it possible to order the results of an SQL query, on a field that is not in the projection itself?

See example below – I am taking the distinct ID of a product table, but I want it ordered by title. I don’t want to include the title because I am using NHibernate to generate a query, and page the results. I am then using this distinct ID resultset, to load the actual results.

SELECT
DISTINCT this_.`ID` AS y0 
FROM
`Product` this_ 
LEFT OUTER JOIN
`Brand` brand3_ 
ON this_.BrandId=brand3_.ID 
INNER JOIN
`Product_CultureInfo` productcul2_ 
ON this_.ID=productcul2_.ProductID 
AND (
(
(
productcul2_.`Deleted` = 0 
OR productcul2_.`Deleted` IS NULL
) 
AND (
productcul2_.`_Temporary_Flag` = 0 
OR productcul2_.`_Temporary_Flag` IS NULL
)
)
) 
INNER JOIN
`ProductCategory` aliasprodu1_ 
ON this_.ID=aliasprodu1_.ProductID 
AND (
(
(
aliasprodu1_.`Deleted` = 0 
OR aliasprodu1_.`Deleted` IS NULL
) 
AND (
aliasprodu1_.`_Temporary_Flag` = 0 
OR aliasprodu1_.`_Temporary_Flag` IS NULL
)
)
) 
WHERE
(
this_._Temporary_Flag =FALSE
OR this_._Temporary_Flag IS NULL
) 
AND this_.Published = TRUE
AND (
this_.Deleted = FALSE
OR this_.Deleted IS NULL
) 
AND (
this_._ComputedDeletedValue = FALSE
OR this_._ComputedDeletedValue IS NULL
) 
AND (
(
this_._TestItemSessionGuid IS NULL 
OR this_._TestItemSessionGuid = ''
)
) 
AND (
productcul2_._ActualTitle LIKE '%silver%' 
OR brand3_.Title LIKE '%silver%' 
OR aliasprodu1_.CategoryId IN (
47906817 , 47906818 , 47906819 , 47906816 , 7012353 , 44662785 
)
) 
AND this_.Published = TRUE
AND this_.Published = TRUE
ORDER BY
this_.Priority ASC,
productcul2_._ActualTitle ASC,
this_.Priority ASC LIMIT 25;

Answer 1

Don’t know if there’s a better solution but how about a nested select where the external query exlude the field that you’re not interested in?

So, something like that on a “random” table

SELECT a,b,c from (SELECT a,b,c,d from myTable order by d)

Obviously if there is a “language-direct” solution will be better because, in that way, you have to do two projection and one of those is useless