using MongoDB.Bson; using MongoDB.Bson.IO; using SqlSugar.MongoDb; using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace MongoDbTest { public class QueryLeftJoin2 { public static void Init() { var db = DbHelper.GetNewDb(); db.DbMaintenance.TruncateTable(); // 添加 City 测试数据 var city1 = new City { Name = "北京" }; var city2 = new City { Name = "上海" }; db.Insertable(city1).ExecuteCommandIdentityIntoEntity(); db.Insertable(city2).ExecuteCommandIdentityIntoEntity(); // 添加 School 测试数据 var school1 = new School { Name = "清华大学", CityId = city1.Id }; var school2 = new School { Name = "复旦大学", CityId = city2.Id }; db.Insertable(school1).ExecuteCommandIdentityIntoEntity(); db.Insertable(school2).ExecuteCommandIdentityIntoEntity(); // 添加 Student 测试数据 var student1 = new Student { Name = "张三", SchoolId = school1.Id }; var student2 = new Student { Name = "李四", SchoolId = school2.Id }; db.Insertable(student1).ExecuteCommandIdentityIntoEntity(); db.Insertable(student2).ExecuteCommandIdentityIntoEntity(); var students = db.Queryable().ToDataTable(); var schools = db.Queryable().ToDataTable(); var cities = db.Queryable().ToDataTable(); var dt=db.Queryable() .LeftJoin((s, sc) => s.SchoolId == sc.Id) .LeftJoin((s, sc, city) => sc.CityId == city.Id) .Select((s, sc, city) => new { studentName=s.Name, schoolName=sc.Name, cityName=city.Name }).ToList(); if (dt.First().schoolName != "清华大学" || dt.First().studentName != "张三" || dt.First().cityName != "北京") Cases.ThrowUnitError(); var dt2 = db.Queryable() .LeftJoin((s, sc) => s.SchoolId == sc.Id) .Select((s, sc) => sc).ToList(); if (dt2.First().Name != "清华大学") Cases.ThrowUnitError(); var dt3 = db.Queryable() .LeftJoin((s, sc) => s.SchoolId == sc.Id) .Select((s, sc) => s).ToList(); if (dt3.First().Name != "张三") Cases.ThrowUnitError(); var dt5 = db.Queryable() .LeftJoin((s, sc) => s.SchoolId == sc.Id ) .Select((s, sc) => new { studentName = s.Name, schoolName = sc.Name }).ToList(); if (dt5.First().studentName != "张三"&& dt5.First().schoolName!= "清华大学") Cases.ThrowUnitError(); //var dt4 = db.Queryable() //.LeftJoin((s, sc) => s.SchoolId.ToLower() == sc.Id) //.Select((s,sc)=>new { // studentName=s.Name, // schoolName=sc.Name //}).ToList(); //if (dt3.First().Name != "张三") Cases.ThrowUnitError(); } [SqlSugar.SugarTable("UnitStudentdu2s31")] public class Student : MongoDbBase { public string Name { get; set; } [SqlSugar.SugarColumn(ColumnDataType = nameof(ObjectId))] public string SchoolId { get; set; } } [SqlSugar.SugarTable("UnitSchool1lki131")] public class School : MongoDbBase { public string Name { get; set; } [SqlSugar.SugarColumn(ColumnDataType = nameof(ObjectId))] public string CityId { get; set; } } [SqlSugar.SugarTable("Cityd1ki131")] public class City : MongoDbBase { public string Name { get; set; } } } }