C# - guide with Dynamic LINQ Query Generating Invalid SQL with Entity Framework Core 6
I'm working with a question while trying to build dynamic LINQ queries using Entity Framework Core 6. Specifically, when I attempt to construct a query based on user-selected filters, it sometimes generates invalid SQL, leading to exceptions like `InvalidOperationException: The LINQ expression could not be converted to an SQL statement.` Here's a simplified version of what I've implemented: ```csharp public IQueryable<Product> GetFilteredProducts(string category, decimal? minPrice, decimal? maxPrice) { var query = _context.Products.AsQueryable(); if (!string.IsNullOrEmpty(category)) { query = query.Where(p => p.Category == category); } if (minPrice.HasValue) { query = query.Where(p => p.Price >= minPrice.Value); } if (maxPrice.HasValue) { query = query.Where(p => p.Price <= maxPrice.Value); } return query; } ``` When `category` is a valid string but `minPrice` and `maxPrice` are both null, it appears to work fine. However, if a user specifies a `minPrice`, then enters an invalid `category`, it throws the aforementioned exception. I thought that using `AsQueryable()` would allow for dynamic filtering, but it seems that when combined, these conditions create a situation where EF Core need to translate the expression. I've also tried debugging with logging enabled to see the generated SQL and it looks like it’s trying to combine conditions that are logically inconsistent. I've attempted to isolate the scenario by creating unit tests for various combinations of inputs, but the question continues. Is there a better way to construct these queries dynamically so that they remain valid regardless of which filters are applied? Any best practices for handling such scenarios would be greatly appreciated.