How to prevent Sql-Injection on User-Generated Sql Queries

Question

I have a project (private, ASP.net website, password protected with https) where one of the requirements is that the user be able to enter Sql queries that will directly query t

Answer 1

One (maybe overkill) option could be use a compiler for a reduced SQL language. Something like using JavaCC with a modified SQL grammar that only allows SELECT statements, then you might receive the query, compile it and if it compiles you can run it.

For C# i know Irony but never used it.