Room supports @RawQuery annotation to construct queries at run-time.

Step 1 : Make DAO method

Mark the DAO method with @RawQuery annotation instead of normal @Query.

@Dao
interface BooksDao{
    @RawQuery
    List<Book> getBooks(SupportSQLiteQuery query);
}

Step 2 : Construct the query

Room uses prepared statements for security and compile time verification. Therefore, while constructing queries, we need to store query string and bind parameters separately.

In this example, I use the variable queryString for query string and args for bind parameters.

^{(Please note that I used text editor to write code. Therefore there may be typo or simple syntax errors. If you find anything please let me know in the comments or edit the post.)}

// Query string
String queryString = new String();

// List of bind parameters
List<Object> args = new ArrayList();

boolean containsCondition = false;

// Beginning of query string
queryString += "SELECT * FROM BOOKS";

// Optional parts are added to query string and to args upon here

if(!authorName.isEmpty()){
    queryString += " WHERE";
    queryString += " author_name LIKE ?%";
    args.add(authorName);
    containsCondition = true;
}

if(fromDate!=null){
    
    if (containsCondition) {
        queryString += " AND";
    } else {
        queryString += " WHERE";
        containsCondition = true;
    }

    queryString += " publication_date AFTER ?";
    args.add(fromDate.getTime());
}

if(toDate!=null){
    
    if (containsCondition) {
        queryString += " AND";
    } else {
        queryString += " WHERE";
        containsCondition = true;
    }

    queryString += " publication_date BEFORE ?";
    args.add(toDate.getTime());
}

// End of query string
queryString += ";";

Step 3 : Perform query

SimpleSQLiteQuery query = new SimpleSQLiteQuery(queryString, args.toArray());
List<Book> result = booksDao.getBooks(query);

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Notes

• Like normal Query, RawQuery supports returning raw cursors, entities, POJOs and POJOs with embedded fields
• RawQuery supports relations