Question

很显然，public List<Animal> GetAnimals(Expression<Func<Animal, bool>> expression) { var animalTypes = GetTypesDerivingFrom(typeof(Animal)); List<Animal> animals = new List<Animal>(); foreach(var animalType in animalTypes) { var typeTranslatedExpression = GetTypeTranslatedExpression(expression); //i dont know how to do this part var portionOfAnimals = context.Set(animalType).Where(typeTranslatedExpression).ToList(); animals.AddRange(portionOfAnimals); } return animals; }无法正常工作，因为我需要聚合整数数据。整数数据的等效功能是什么：

string_agg

预先感谢

Answer 1

您可以像这样将int用作运算符::的字符串：

SELECT the_geom, 
       string_agg(profile_id::text || ', ' || upper_dept::text, || ', ' ||lower_dept::text, || ', ' ||phaq_val_1::text, '; ' ORDER BY upper_dept) AS pH_info
FROM ph_agua_1 
GROUP BY the_geom

PostgreSQL聚合函数用于整数数据

1 个答案: