Room DAO Order By ASC or DESC variable

Question

I\'m trying to make a @Query function in my @Dao interface which has a boolean parameter, isAsc to determine the order:

@Q         


        

Answer 1

Use CASE Expression for SQLite to achieve this in Room DAO,

@Query("SELECT * FROM Persons ORDER BY 
        CASE WHEN :isAsc = 1 THEN first_name END ASC, 
        CASE WHEN :isAsc = 0 THEN first_name END DESC")
List getPersonsAlphabetically(boolean isAsc);