Search returns 500 error with MSSQL

[izzor]

• Gitea version (or commit ref): 1.6
• Git version: 2.7.4
• Operating system: Ubuntu 16.04
• Database (use [x]):
  • PostgreSQL
  • MySQL
  • MSSQL
  • SQLite
• Can you reproduce the bug at https://try.gitea.io:
  • Yes (provide example URL)
  • No
  • [] Not relevant
• Log gist:
  [2018/10/23 09:58:55 [I] [SQL] SELECT TOP 20 repository.* FROM "repository" LEFT JOIN repo_topic ON repo_topic.repo_id = repository.id LEFT JOIN topic ON repo_topic.topic_id = topic.id WHERE (owner_id=? OR ((repository.id IN (SELECT repo_id FROM "access" WHERE access.user_id = ?)) AND owner_id<>?) OR is_private=?) AND (lower_name LIKE ? OR topic.name LIKE ?) GROUP BY repository.id ORDER BY repository.updated_unix DESC []interface {}{2, 2, 2, false, "%foobar%", "%foobar%"}]
  [2018/10/23 09:58:55 [...itea/routers/home.go:138 RenderRepoSearch()] [E] SearchRepositoryByName: Repo: mssql: Column 'repository.owner_id' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.]

Description

When using the search field under Explore / Repositories I get a 500, Internal Server Error. I checked the log files and found the query causing the error.
In MS SQL Server all columns must be specified in the Group By clause. MySQL allows it but I guess it may be a problem with other database dialects as well.

[alexmejiaec]

bump

[lunny]

#5136 will try to fix this issue.