Net/NetCore/.NET5 ORM 六大查询体系

框架介绍

SqlSugar ORM是一款老牌国产ORM框架，生命力也比较顽强，从早期ORM不成熟阶段，一直存活到现在，我为什么要一直坚持，那是因为还有很多用户在使用，本来我能够较早推出新开源框架 ，可是用户还在不停的提新的需求和高的要求，所以我也尽我最大努力将SqlSugar更加完善

1、有人说不支持国产数据库 我支持了

2、有人说 PgSql MySql Oracle兼容性不好，经过努力我也让他成熟了

3、有人说SqlSugar异步是Task.RUN，我也将SqlSugar升级到NET 4.5支持了原生异步

4、有人说导航支持不给力 ，我也让他开始给力

5、有人说不支持多级插入，我也支持了

我不能保证6年来每个用户的需求都能够支持，但是我能保证多个用户提出了一样的需求，那我就需要好好设计并且满足他们

本文重点

SqlSugar查询非常的丰富多彩，且这些功能也有非常高的实用性，我将SqlSugar的查询做了一个整理和分类：

1、基础查询  

2、联表查询

3、子查询

4、导航查询

5、查询结果

6、高级查询

一、基础查询

基础查询从字面意思 就是最常用最简单的查询

var getAll = db.Queryable<Student>().ToList();//查询所有
var top10= db.Queryable<Student>().Take(10).ToList();//查询前10
var getFirst = db.Queryable<Student>().First(it=>it.Id==1);//查询单条
var getAllNoLock = db.Queryable<Student>().With(SqlWith.NoLock).ToList();//SqlServer里面的withnolock
var getByPrimaryKey = db.Queryable<Student>().InSingle(2);//根据主键查询
var sum = db.Queryable<Student>().Sum(it=>it.Id);//查询总和
var isAny = db.Queryable<Student>().Where(it=>it.Id==-1).Any();//是否存在
var isAny2 = db.Queryable<Student>().Any(it => it.Id == -1);
var getListByRename = db.Queryable<School>().AS("Student").ToList();
var getByWhere = db.Queryable<Student>().Where(it => it.Id == 1 || it.Name == "a").ToList();
var list= db.Queryable<Student>().AS("student2019").ToList();//select * from student2019
var list2 = db.Queryable<Order>().Where(it =>it.Name.Contains("jack")).ToList();//模糊查询 name like '%'+@name+'%'

分组查询

var list = db.Queryable<Student>()
             .GroupBy(it => new { it.Id, it.Name })
             .Having(it => SqlFunc.AggregateAvg(it.Id) > 0)//不是聚合函数用Where就可以了
             .Select(it => new { idAvg = SqlFunc.AggregateAvg(it.Id), name = it.Name })
             .ToList();
//SELECT AVG([Id]) AS[idAvg], [Name] AS[name]  FROM[Student] GROUP BY[Name],[Id] HAVING(AVG([Id]) > 0 )

分页查询

//同步分页 
 int pageIndex = 1; 
 int pageSize = 20;
 int totalCount=0;
 var page = db.Queryable<Student>().ToPageList(pageIndex, pageSize, ref totalCount);

并集合查询

 var q1 = db.Queryable<Student>().Select(it=>new Model{ name=it.Name });
 var q2 = db.Queryable<School>().Select(it => new Model { name = it.Name });
 var list = db.UnionAll(q1, q2).ToList();
SELECT * FROM  (SELECT  [Name] AS [name]  FROM [STudent]  UNION ALL
SELECT  [Name] AS [name]  FROM [School] ) unionTable

二、联表查询

1.两表查询将结果返回匿名对象

var list = db.Queryable<Student, School>((st, sc) => new JoinQueryInfos(JoinType.Left,st.SchoolId==sc.Id))
      .Select((st,sc)=>new{Id=st.Id,Name=st.Name,SchoolName=sc.Name})
      .ToList();

生成的Sql如下:

SELECT  [st].[ID] AS [id] , 
          [st].[Name] AS [name] , 
          [sc].[Name] AS [schoolName]  FROM [STudent] st 
          Left JOIN School sc ON ( [st].[SchoolId] =[sc].[Id])

2、联表查询将结果返回到新类,实现  Select a.*,  b.name as bname

var oneClass = db.Queryable<Order, OrderItem, Custom>((o, i, c) => new JoinQueryInfos(
    JoinType.Left, o.Id == i.OrderId,
    JoinType.Left, o.CustomId == c.Id
))
.Select((o,i,c)=> new ViewOrder// 是一个新类
{
   Id=SqlFunc.GetSelfAndAutoFill(o.Id),// 等于 o.*
   CustomName=c.Name   // 等于 [c].[Name] AS [CustomName]
}).ToList()

3.按规则自动填充

需要注意的是 Select用的是自动填充这样使用方便，高并发的地方还是写成上面那种方式

 public class ViewModelStudent : Student
 {
        public string SchoolName{get;set;}// 类名 + 属性名
 }
 var list = db.Queryable<Student, School, DataTestInfo>((st, sc, di) => new JoinQueryInfos(
              JoinType.Left,st.SchoolId==sc.Id,//可以用&&实现 on 条件 and
              JoinType.Left,st.Name==di.String
            ))
           //.Where((st,sc)=>sc.id>0) 多表条件用法
           .Select<ViewModelStudent>().ToList();
  
 //SELECT 
    //sc.[Name] AS [SchoolName],--自动生成 SchoolName
      //st.[ID] AS [Id],st.[SchoolId] AS [SchoolId],
      //st.[Name] AS [Name],st.[CreateTime] AS [CreateTime]
      //FROM [STudent] st
      //Left JOIN [School] sc ON ( [st].[SchoolId] = [sc].[Id] )  
      //Left JOIN [DataTestInfo] di ON ( [st].[Name] = [di].[String] )

4、简单联表

var list = db.Queryable<Order, OrderItem, Custom>((o, i, c) => o.Id == i.OrderId&&c.Id == o.CustomId)
                .Select<ViewOrder>()
                .ToList();

 生成的Sql:

SELECT  c.[Name] AS [CustomName],
        o.[Id] AS [Id],o.[Name] AS [Name],
        o.[Price] AS [Price],
        o.[CreateTime] AS [CreateTime],
        o.[CustomId] AS [CustomId]         FROM [Order] o  ,[OrderDetail]  i ,[Custom]  c  
         WHERE (( [o].[Id] = [i].[OrderId] ) AND ( [c].[Id] = [o].[CustomId] ))

三、子查询

SqlSugar的子查询也是非常的强大，很多人都问

1. 子查询查一列

var getAll = db.Queryable<Student, School>((st, sc) => new JoinQueryInfos(JoinType.Left,st.Id==sc.Id))
.Where(st => st.Id == SqlFunc.Subqueryable<School>().Where(s => s.Id == st.Id).Select(s => s.Id))
.ToList();

 生成的Sql如下

SELECT `st`.`ID`,`st`.`SchoolId`,`st`.`Name`,`st`.`CreateTime` 
FROM `STudent` st Left JOIN `School` sc ON ( `st`.`ID` = `sc`.`Id` ) 
WHERE ( `st`.`ID` =(SELECT `Id` FROM `School` WHERE ( `Id` = `st`.`ID` ) limit 0,1))

在select中也可以使用

var getAll = db.Queryable<Student, School>((st, sc) => new JoinQueryInfos(JoinType.Left,st.Id==sc.Id))
.Select(st => new{
name = st.Name,
id = SqlFunc.Subqueryable<School>().Where(s => s.Id == st.Id).Select(s => s.Id)
}).ToList();

同时Subquery也支持了Join

.LeftJoin<OrderItem>((cus,item)=>cus.Id==item.CustomId /* 用 && 追加条件 */)

2.IN和NOT IN的操作

var getAll7 = db.Queryable<Student>().Where(it => 
SqlFunc.Subqueryable<School>().Where(s => s.Id == it.Id).Any()).ToList();

/*生成的SQL(等于同于it.id in(select id from school)只是写法不一样
SELECT `ID`,`SchoolId`,`Name`,`CreateTime` FROM `STudent` it 
WHERE (EXISTS ( SELECT * FROM `School` WHERE ( `Id` = `it`.`ID` ) )) 
*/


var getAll8 = db.Queryable<Student>().Where(it => 
SqlFunc.Subqueryable<School>().Where(s => s.Id == it.Id).NotAny()).ToList();

/*生成的SQL
SELECT `ID`,`SchoolId`,`Name`,`CreateTime` FROM `STudent` it 
WHERE (NOT EXISTS ( SELECT * FROM `School` WHERE ( `Id` = `it`.`ID` ) ))
*/

3、联表子查询

当你要用一个表和一个联进行联查询的时候，或者2个联表在进行联表查询的时候都可以用这种方式实现

var query1 = db.Queryable<Student, School>((st, sc) => new JoinQueryInfos(JoinType.Left,st.SchoolId==sc.Id))
.Where(st => st.Name == "jack");

var query2 = db.Queryable<DataTestInfo>();

db.Queryable(query1, query2, (p1, p2) => p1.Id == p2.Int1).Select<ViewModelStudent>().ToList();


//SELECT * FROM 
// (SELECT [st].[ID],[st].[SchoolId],[st].[Name],[st].[CreateTime] 
// FROM [STudent] st 
// Left JOIN [School] sc ON ([st].[SchoolId]=[sc].[Id] ) 
// WHERE ( [st].[Name] = @Name0Join0 )) p1 
//
// Inner JOIN

// (SELECT [Int1],[Int2],[String],[Decimal1],[Decimal2],
// [Datetime1],[Datetime2],[Image1],[Image2], 
// [Guid1],[Guid2],[Money1],[Money2],[Varbinary1],
// [Varbinary2],[Float1],[Float2] FROM [DataTestInfo] )p2 

// ON ( [p1].[ID] = [p2].[Int1] )

4、多合一子查询

一般多表查询后 动态使用搜索条件和排序 需要使用 st sc等前缀，多表合成一后变成了单表查询 所以都不需要加别名了

var pageJoin = db.Queryable<Student, School>((st, sc) => new JoinQueryInfos(JoinType.Left,st.SchoolId==sc.Id))
.Select((st,sc) => new{ 
                        id = st.Id,
                        name = sc.Name})
.MergeTable()
.Where(it=>it.id==1).OrderBy("name asc").ToList();

生成的Sql如下：

SELECT * FROM

(SELECT 
[st].[Id] AS [id] , [sc].[Name] AS [name] 
FROM [Student] st Left 
JOIN [School] sc ON ( [st].[CustomId] = [sc].[Id] ) ) MergeTable--将结果变成一个表 

WHERE ( [id] = @id0 )ORDER BY name asc

5、一合一的子查询

我只是想单表外面在包一层 你可以这样实现，和MergetTable区别在于前者需要加上Select后者不需要

var listx=db.Queryable(db.Queryable<Order>()).ToList();

 Sql代码如下：

SELECT t.* FROM (SELECT [Id],[Name],[Price],[CreateTime],[CustomId] FROM [Order] ) t

四、导航查询

1、无配置开箱就用

对于其它ORM导航查询来说一般都需要实体配置实体的关联关系，而SqlSugar则开箱就用，除了给非数据库字段加上Ignore外没有任何配置

2、高性能

自动映射模式不会产生循环Sql读取的情况，比如一对多查询 查询1条记录 那么生成2条SQL，那么查询200条记录还是生成2条SQL，

有人说为什么是2条而不是1条呢，1条复杂的sql性能未必好过2条简单无聚合分组的sql，可以通在sqlserver界面把3条sql扔进去然后

看执行计划的开销比例，如果说1条Sql大于等于50%那么他的性能就低于2条SQL性能

1、一对一查询

使用Mapper一对一模式需要设置2-3个参数， Mapper( 1需要填充的子对象 ,2主表关联字段，3从表关联字段（默认为从表主键）)

第一个参数：it.Order是填充的子对象

第二个参数 it.OrderId是主表中关联字段

第三个参数 不填等于从表主键，也可以指定从表某个字段

其实就是 主表中的 it.OrderId 和从表中的主键进行关联 ，就能自动填充到 OrderItem.Order里面

var list= db.Queryable<OrderItem>().Mapper(it => it.Order, it => it.OrderId).ToList(); 
foreach(var item in list)
{
   Console.WriteLine(item.Order.Name);//输出子对象中的值
}
 
//新功能： 1对1模式中支持了条件过滤
var list= db.Queryable<OrderItem>()
.Mapper(it => it.Order, it => it.OrderId)
.Where(it=>it.Order.Name=="哈哈").ToList(); //我们可以使用2级对象属性进行筛选

public class OrderItem {
 [SugarColumn(IsPrimaryKey =true ,IsIdentity =true)]
 public int ItemId { get; set; }
 public string ItemCode { get; set; }
 public decimal Pirce { get; set; }
 public int OrderId { get; set; }
 [SugarColumn(IsIgnore =true)]
 public Order Order{ get; set; }
}
public class Order {
 [SugarColumn(IsPrimaryKey = true, IsIdentity = true)]
 public int Id { get; set; }
 public string Name { get; set; }
}

　　

2、一对多查询

var list= db.Queryable<Order>().Mapper(it => it.Items, it => it.Items.First().OrderId).ToList();

public class Order
{
 [SugarColumn(IsPrimaryKey = true, IsIdentity = true)]
 public int Id { get; set; }
 public string Name { get; set; }
 [SugarColumn(IsIgnore = true)]
 public List<OrderItem> Items { get; set; }
}

3、 多对多查询

public class ABMapping
{
  [SugarColumn(IsPrimaryKey = true, IsIdentity = true)]
  public int AId { get; set; }
  public int BId { get; set; }
  [SugarColumn(IsIgnore = true)]
  public A A { get; set; }
  [SugarColumn(IsIgnore = true)]
  public B B { get; set; }
}
public class A {
 [SugarColumn(IsPrimaryKey =true ,IsIdentity =true)]
   public int Id { get; set; }
  public string Name { get; set; }
}
public class B
{
  [SugarColumn(IsPrimaryKey = true, IsIdentity = true)]
  public int Id { get; set; }
  public string Name { get; set; }
}
var list= db.Queryable<ABMapping>()
.Mapper(it => it.A,it=>it.AId)
.Mapper(it => it.B, it => it.BId).ToList();

4、 相同字段名映射

子表对象=子表对象.where(it=>it.OrgId==主表对象中的.OrgId)

var list= db.Queryable<A>().Mapper(it => it.B,it=>it.OrgId).ToList();

　　

 五、查询结果

支持常用的 类、匿名类、数组、字典、字典集合、JSON、DataTable、树

//返回List
List<Student> list = db.Queryable<Student>().ToList();
//返回DataTable
DataTable dataTable = db.Queryable<Student>().Select(it => it.Id).ToDataTable();
//返回Json
var json = db.Queryable<Student>().ToJson();
//返回数组
List<int> listInt=db.Queryable<Student>().Select(it => it.Id).ToList();　　
//返回匿名对象
var dynamic = db.Queryable<Student>().Select<dynamic>().ToList();　　
//表达式返回字典
Dictionary<string,object> dc = db.Queryable<Order>().ToDictionary(it=>it.Id,it=>it.Name);
//返回字典集合
List<Dictionary<string, object>> dcList = db.Queryable<Order>().ToDictionaryList();;

Tree树结果

var tree = db.Queryable<Tree>().ToTree(it=>it.Child,it=>it.ParentId,0); //第三个参数为0代表 parent为0是第一级
//实体
public class Tree
{
 [SqlSugar.SugarColumn(IsPrimaryKey =true)]
 public int Id { get; set; }
 public string Name { get; set; }
 public int ParentId { get; set; }
 [SqlSugar.SugarColumn(IsIgnore = true)]
 public List<Tree> Child { get; set; }
}

六、高级查询

二缓缓存是将结果集进行缓存，当SQL和参数没发生变化的时候从缓存里面读取数据，减少数据库的读取操作

ICacheService myCache = new HttpRuntimeCache();
SqlSugarClient db = new SqlSugarClient(new ConnectionConfig()
{
  ConnectionString = Config.ConnectionString,
  DbType = DbType.SqlServer,
  IsAutoCloseConnection = true,
  ConfigureExternalServices = new ConfigureExternalServices()
  {
    DataInfoCacheService = myCache //配置我们创建的缓存类
  }
});
db.Queryable<Student>().Where(it => it.Id > 0).WithCache().ToList();//设置缓存默认一天
db.Queryable<Student>().WithCache(1000).ToList();//设置具体过期时间

异步查询

var task1=db.Queryable<Order>().FirstAsync();
var task2 = db.Queryable<Order>().Where(it=>it.Id==1).ToListAsync();
 
//分页需要特别注意用法
RefAsync<int> total = 0;
Db.Queryable<Order>().ToPageListAsync(1, 2, total);

Json类型查询

public class UnitJsonTest
{
   [SqlSugar.SugarColumn(IsPrimaryKey = true, IsIdentity = true)]
   public int Id { get; set; }
    [SqlSugar.SugarColumn(ColumnDataType ="varchar(2000)", IsJson = true)]
   public Order Order { get; set; }
   public string Name{get;set;}
}
Db.Insertable(new UnitJsonTest() { Name="json1",Order = new Order { Id = 1, Name = "order1" } }).ExecuteCommand();
var list = Db.Queryable<UnitJsonTest>().ToList();

动态表达式查询

var exp= Expressionable.Create<Student>()
                .And(it=>it.Id==1)
                .Or(it =>it.Name.Contains("jack")).ToExpression();
var list=db.Queryable<Student>().Where(exp).ToList();

动态条件查询

var conModels = new List<IConditionalModel>();
conModels.Add(new ConditionalModel{ FieldName = "id", ConditionalType = ConditionalType.Equal, FieldValue = "1"}); 
var student = db.Queryable<Student>().Where(conModels).ToList();

　　

 SqlSugar源码下载：

https://github.com/donet5/SqlSugar

没点关注的点一波关注，我不能保证SqlSugar现在就是最好，便是未来会越来越好 ，谢谢 

 新的开源框架WebFirst也在开发中，预计春节前发布,将支持 web和exe