Use joins instead of sub-queries in group by/sort by when using custom fields (#12713).

Sub-queries in group by are not supported by SQLServer.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@11102 e93f8b46-1217-0410-a6f0-8f06a7374b81
Make sure we don't cast an empty string to numeric (#12713).

SQLServer evaluates the CAST condition even if the <> '' condition is false.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@11103 e93f8b46-1217-0410-a6f0-8f06a7374b81
Fixed fixtures.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@11104 e93f8b46-1217-0410-a6f0-8f06a7374b81
Don't do any query if id is not present.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@11105 e93f8b46-1217-0410-a6f0-8f06a7374b81
A column has been specified more than once in the order by list (#12713).

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@11106 e93f8b46-1217-0410-a6f0-8f06a7374b81
Use joins instead of sub-queries (#12713).

Sub-queries in group by are not supported by SQLServer.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@11107 e93f8b46-1217-0410-a6f0-8f06a7374b81
Code cleanup.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@11108 e93f8b46-1217-0410-a6f0-8f06a7374b81