/// <summary>
/// Sql查询
/// </summary>
private void SqlQuery()
{
using (var db = SugarDao.GetInstance())
{
//转成list
List <Student> list1 = db.SqlQuery <Student>("select * from Student");
//转成list带参
List <Student> list2 = db.SqlQuery <Student>("select * from Student where id=@id", new { id = 1 });
//转成dynamic
dynamic list3 = db.SqlQueryDynamic("select * from student");
//转成json
string list4 = db.SqlQueryJson("select * from student");
//返回int
var list5 = db.SqlQuery <int>("select top 1 id from Student").SingleOrDefault();
//反回键值
Dictionary <string, string> list6 = db.SqlQuery <KeyValuePair <string, string> >("select id,name from Student").ToDictionary(it => it.Key, it => it.Value);
//反回List<string[]>
var list7 = db.SqlQuery <string[]>("select top 1 id,name from Student").SingleOrDefault();
//存储过程
var spResult = db.SqlQuery <School>("exec sp_school @p1,@p2", new { p1 = 1, p2 = 2 });
//获取第一行第一列的值
string v1 = db.GetString("select '张三' as name");
int v2 = db.GetInt("select 1 as name");
double v3 = db.GetDouble("select 1 as name");
decimal v4 = db.GetDecimal("select 1 as name");
}
}
public void Init()
{
using (SqlSugarClient db = SugarDao.GetInstance())//开启数据库连接
{
Student s = new Student()
{
name = "张" + new Random().Next(1, int.MaxValue)
};
db.Insert(s); //插入一条记录 (有主键也好，没主键也好，有自增列也好都可以插进去)
List <Student> list = new List <Student>()
{
new Student()
{
name = "张" + new Random().Next(1, int.MaxValue)
},
new Student()
{
name = "张" + new Random().Next(1, int.MaxValue)
}
};
db.InsertRange(list); //批量插入
}
}
/// <summary>
/// 新容器转换
/// </summary>
private void NewSelect()
{
using (SqlSugarClient db = SugarDao.GetInstance())
{
var list2 = db.Queryable <Student>().Where(c => c.id < 10).Select(c => new classNew {
newid = c.id, newname = c.name, xx_name = c.name
}).ToList(); //不支持匿名类转换,也不建议使用
var list3 = db.Queryable <Student>().Where(c => c.id < 10).Select(c => new { newid = c.id, newname = c.name, xx_name = c.name }).ToDynamic(); //匿名类转换
}
}
public void Init()
{
using (SqlSugarClient db = SugarDao.GetInstance())//开启数据库连接
{
var r1 = db.GetDataTable("select * from student");
var r2 = db.GetSingle <Student>("select top 1 * from student");
var r3 = db.GetScalar("select count(1) from student");
var r4 = db.GetReader("select count(1) from student");
r4.Dispose();
var r5 = db.GetString("select top 1 name from student");
var r6 = db.ExecuteCommand("select 1");
}
}
public void Init()
{
using (SqlSugarClient db = SugarDao.GetInstance())//开启数据库连接
{
Student s = new Student()
{
name = "张" + new Random().Next(1, int.MaxValue)
};
db.Insert(s); //插入一条记录 (有主键也好，没主键也好，有自增列也好都可以插进去)
List <Student> list = new List <Student>()
{
new Student()
{
name = "张" + new Random().Next(1, int.MaxValue)
},
new Student()
{
name = "张" + new Random().Next(1, int.MaxValue)
}
};
db.InsertRange(list); //批量插入
//高性能批量插入
//注意:性能比InsertRange高，功能没有InsertRange全,不支持别名表和排除列
using (SqlSugarClient db2 = SugarDao.GetInstance())//开启数据库连接
{
var list2 = new List <Student>()
{
new Student()
{
isOk = true, name = "张三", sch_id = 1, sex = "男"
},
new Student()
{
isOk = true, name = "sun", sch_id = 1, sex = "女"
},
new Student()
{
isOk = true, name = "mama", sch_id = 1, sex = "gril"
}
};
db.SqlBulkCopy <Student>(list2);
}
}
}
/// <summary>
/// 新容器转换
/// </summary>
private void NewSelect()
{
using (SqlSugarClient db = SugarDao.GetInstance())
{
var list2 = db.Queryable <Student>().Where(c => c.id < 10).Select(c => new classNew {
newid = c.id, newname = c.name, xx_name = c.name
}).ToList(); //不支持匿名类转换,也不建议使用
var list3 = db.Queryable <Student>().Where(c => c.id < 10).Select(c => new { newid = c.id, newname = c.name, xx_name = c.name }).ToDynamic(); //匿名类转换
var list4 = db.Queryable <Student>().Where(c => c.id < 10).Select("id as newid, name as newname ,name as xx_name").ToDynamic(); //匿名类转换
var jList1 = db.Queryable <Student>()
.JoinTable <Student, School>((s1, s2) => s1.sch_id == s2.id) // left join School s2 on s1.id=s2.id
.Where <Student, School>((s1, s2) => s1.id > 1) // where s1.id>1
.OrderBy <Student, School>((s1, s2) => s1.id) //order by s1.id 多个order可以 .oderBy().orderby 叠加
.Skip(1)
.Take(2)
.Select <Student, School, classNew>((s1, s2) => new classNew()
{
newid = s1.id, newname = s2.name, xx_name = s1.name
}) //select目前只支持这种写法
.ToList();
var jList2 = db.Queryable <Student>()
.JoinTable <Student, School>((s1, s2) => s1.sch_id == s2.id) // left join School s2 on s1.id=s2.id
.Where <Student, School>((s1, s2) => s1.id > 1) // where s1.id>1
.OrderBy <Student, School>((s1, s2) => s1.id) //order by s1.id 多个order可以 .oderBy().orderby 叠加
.Skip(1)
.Take(2)
.Select <Student, School, classNew>((s1, s2) => new classNew()
{
newid = s1.id, newname = s1.name, xx_name = s1.name
}) //select目前只支持这种写法
.ToDynamic();
var jList3 = db.Queryable <Student>()
.JoinTable <Student, School>((s1, s2) => s1.sch_id == s2.id) // left join School s2 on s1.id=s2.id
.Where <Student, School>((s1, s2) => s1.id > 1) // where s1.id>1
.OrderBy <Student, School>((s1, s2) => s1.id) //order by s1.id 多个order可以 .oderBy().orderby 叠加
.Skip(1)
.Take(2)
.Select <Student, classNew>(s1 => new classNew()
{
newid = s1.id, newname = s1.name, xx_name = s1.name
}) //select目前只支持这种写法
.ToDynamic();
}
}
public void Init()
{
using (var db = SugarDao.GetInstance())
{
//真删除
db.Delete <School, int>(10);//注意主键必需为实体类的第一个属性
db.Delete <School>(it => it.id > 100);
db.Delete <School, string>(new string[] { "100", "101", "102" });
//假删除
//db.FalseDelete<school>("is_del", 100);
//等同于 update school set is_del=0 where id in(100)
//db.FalseDelete<school>("is_del", it=>it.id==100);
}
}
public void Init()
{
using (SqlSugarClient db = SugarDao.GetInstance())
{
var stuList = db.Queryable <Student>().ToList();
db.Insert <Student>(new Student()
{
sch_id = SchoolEnum.蓝翔2
});
db.Update <Student>(new Student()
{
sch_id = SchoolEnum.蓝翔1, id = 1
});
var stuList2 = db.Queryable <Student>().Where(it => it.sch_id == SchoolEnum.蓝翔1).ToList();
}
}
public void Init()
{
using (var db = SugarDao.GetInstance())
{
//根据当前数据库生成所有表的实体类文件 （参数：SqlSugarClient ，文件目录，命名空间）
db.ClassGenerating.CreateClassFiles(db, @"D:\SqlSugarModelFiles2", "Models");
//根据表名生成实体类文件
//db.ClassGenerating.CreateClassFilesByTableNames(db, Server.MapPath("~/Models"), "Models" , "student","school");
//根据表名生成class字符串
var str = db.ClassGenerating.TableNameToClass(db, "Student");
//根据SQL语句生成class字符串
var str2 = db.ClassGenerating.SqlToClass(db, "select top 1 * from Student", "student");
}
}
public void Init()
{
using (SqlSugarClient db = SugarDao.GetInstance()) //开启数据库连接
{
db.IsNoLock = true; //启用无锁查询
db.CommandTimeOut = 30000; //设置超时时间
try
{
db.BeginTran();//开启事务
//db.BeginTran(IsolationLevel.ReadCommitted);+3重载可以设置事世隔离级别
db.CommitTran();//提交事务
}
catch (Exception)
{
db.RollbackTran();//回滚事务
throw;
}
}
}
public void Init()
{
int id = 10;
using (var db = SugarDao.GetInstance())
{
//指定列更新
db.Update <School>(new { name = "蓝翔2" }, it => it.id == id);
db.Update <School, int>(new { name = "蓝翔2" }, 10, 13, 12);
db.Update <School, string>(new { name = "蓝翔2" }, new string[] { "11", "12" });
//整个实体更新
db.Update(new School {
id = id, name = "蓝翔2"
});
db.Update <School>(new School {
id = id, name = "蓝翔2"
}, it => it.id == id);
//设置不更新列
db.DisableUpdateColumns = new string[] { "CreateTime" };//设置CreateTime不更新
TestUpdateColumns updObj = new TestUpdateColumns()
{
VGUID = Guid.Parse("542b5a27-6984-47c7-a8ee-359e483c8470"),
Name = "xx",
Name2 = "xx2",
IdentityField = 0,
CreateTime = null
};
//CreateTime将不会被更新
db.Update(updObj);
//以前实现这种更新需要用指定列的方式实现，现在就简单多了。
}
}
/// <summary>
/// 单表查询
/// </summary>
private void QueryableDemo()
{
using (var db = SugarDao.GetInstance())
{
//---------Queryable<T>,扩展函数查询---------//
//针对单表或者视图查询
//查询所有
var student = db.Queryable <Student>().ToList();
var studentDynamic = db.Queryable <Student>().ToDynamic();
var studentJson = db.Queryable <Student>().ToJson();
//查询单条
var single = db.Queryable <Student>().Single(c => c.id == 1);
//查询单条没有记录返回空对象
var single2 = db.Queryable <Student>().Where(c => c.id == 1).SingleOrDefault();
//查询第一条
var first = db.Queryable <Student>().Where(c => c.id == 1).First();
var first2 = db.Queryable <Student>().Where(c => c.id == 1).FirstOrDefault();
//取10-20条
var page1 = db.Queryable <Student>().Where(c => c.id > 10).OrderBy(it => it.id).Skip(10).Take(20).ToList();
//上一句的简化写法，同样取10-20条
var page2 = db.Queryable <Student>().Where(c => c.id > 10).OrderBy(it => it.id).ToPageList(2, 10);
//查询条数
var count = db.Queryable <Student>().Where(c => c.id > 10).Count();
//从第2条开始以后取所有
var skip = db.Queryable <Student>().Where(c => c.id > 10).OrderBy(it => it.id).Skip(2).ToList();
//取前2条
var take = db.Queryable <Student>().Where(c => c.id > 10).OrderBy(it => it.id).Take(2).ToList();
// Not like
string conval = "a";
var notLike = db.Queryable <Student>().Where(c => !c.name.Contains(conval.ToString())).ToList();
//Like
conval = "三";
var like = db.Queryable <Student>().Where(c => c.name.Contains(conval)).ToList();
// 可以在拉姆达使用 ToString和 Convert,比EF出色的地方
var convert1 = db.Queryable <Student>().Where(c => c.name == "a".ToString()).ToList();
var convert2 = db.Queryable <Student>().Where(c => c.id == Convert.ToInt32("1")).ToList();//
var convert3 = db.Queryable <Student>().Where(c => DateTime.Now > Convert.ToDateTime("2015-1-1")).ToList();
var convert4 = db.Queryable <Student>().Where(c => DateTime.Now > DateTime.Now).ToList();
//支持字符串Where 让你解决，更复杂的查询
var student12 = db.Queryable <Student>().Where(c => "a" == "a").Where("id>100").ToList();
var student13 = db.Queryable <Student>().Where(c => "a" == "a").Where("id>100 and id in( select 1)").ToList();
//存在记录反回true，则否返回false
bool isAny100 = db.Queryable <Student>().Any(c => c.id == 100);
bool isAny1 = db.Queryable <Student>().Any(c => c.id == 1);
//获取最大Id
object maxId = db.Queryable <Student>().Max(it => it.id);
int maxId1 = db.Queryable <Student>().Max(it => it.id).ObjToInt(); //拉姆达
int maxId2 = db.Queryable <Student>().Max <Student, int>("id"); //字符串写法
//获取最小
int minId1 = db.Queryable <Student>().Where(c => c.id > 0).Min(it => it.id).ObjToInt(); //拉姆达
int minId2 = db.Queryable <Student>().Where(c => c.id > 0).Min <Student, int>("id"); //字符串写法
//order By
var orderList = db.Queryable <Student>().OrderBy("id desc,name asc").ToList(); //字符串支持多个排序
//可以多个order by表达示
var order2List = db.Queryable <Student>().OrderBy(it => it.name).OrderBy(it => it.id, OrderByType.desc).ToList(); // order by name as ,order by id desc
//In
var intArray = new[] { "5", "2", "3" };
var intList = intArray.ToList();
var list0 = db.Queryable <Student>().In(it => it.id, 1, 2, 3).ToList();
var list1 = db.Queryable <Student>().In(it => it.id, intArray).ToList();
var list2 = db.Queryable <Student>().In("id", intArray).ToList();
var list3 = db.Queryable <Student>().In(it => it.id, intList).ToList();
var list4 = db.Queryable <Student>().In("id", intList).ToList();
//分组查询
var list7 = db.Queryable <Student>().Where(c => c.id < 20).GroupBy(it => it.sex).Select("sex,Count=count(*)").ToDynamic();
var list8 = db.Queryable <Student>().Where(c => c.id < 20).GroupBy(it => it.sex).GroupBy(it => it.id).Select("id,sex,Count=count(*)").ToDynamic();
List <SexTotal> list9 = db.Queryable <Student>().Where(c => c.id < 20).GroupBy(it => it.sex).Select <Student, SexTotal>("Sex,Count=count(*)").ToList();
List <SexTotal> list10 = db.Queryable <Student>().Where(c => c.id < 20).GroupBy("sex").Select <Student, SexTotal>("Sex,Count=count(*)").ToList();
//SELECT Sex,Count=count(*) FROM Student WHERE 1=1 AND (id < 20) GROUP BY Sex --生成结果
//2表关联查询
var jList = db.Queryable <Student>()
.JoinTable <Student, School>((s1, s2) => s1.sch_id == s2.id) //默认left join
.Where <Student, School>((s1, s2) => s1.id == 1)
.Select("s1.*,s2.name as schName")
.ToDynamic();
/*等于同于
* SELECT s1.*,s2.name as schName
* FROM [Student] s1
* LEFT JOIN [School] s2 ON s1.sch_id = s2.id
* WHERE s1.id = 1 */
//2表关联查询并分页
var jList2 = db.Queryable <Student>()
.JoinTable <Student, School>((s1, s2) => s1.sch_id == s2.id) //默认left join
//如果要用inner join这么写
//.JoinTable<Student, School>((s1, s2) => s1.sch_id == s2.id ,JoinType.INNER)
.Where <Student, School>((s1, s2) => s1.id > 1)
.OrderBy <Student, School>((s1, s2) => s1.name)
.Skip(10)
.Take(20)
.Select("s1.*,s2.name as schName")
.ToDynamic();
//3表查询并分页
var jList3 = db.Queryable <Student>()
.JoinTable <Student, School>((s1, s2) => s1.sch_id == s2.id) // left join School s2 on s1.id=s2.id
.JoinTable <Student, School>((s1, s3) => s1.sch_id == s3.id) // left join School s3 on s1.id=s3.id
.Where <Student, School>((s1, s2) => s1.id > 1) // where s1.id>1
.Where <Student>(s1 => s1.id > 0)
.OrderBy <Student, School>((s1, s2) => s1.id) //order by s1.id 多个order可以 .oderBy().orderby 叠加
.Skip(10)
.Take(20)
.Select("s1.*,s2.name as schName,s3.name as schName2")//select目前只支持这种写法
.ToDynamic();
//上面的方式都是与第一张表join，第三张表想与第二张表join写法如下
List <classNew> jList4 = db.Queryable <Student>()
.JoinTable <Student, School>((s1, s2) => s1.sch_id == s2.id) // left join School s2 on s1.id=s2.id
.JoinTable <Student, School, Area>((s1, s2, a1) => a1.id == s2.AreaId) // left join Area a1 on a1.id=s2.AreaId
.Select <Student, School, Area, classNew>((s1, s2, a1) => new classNew {
newid = s1.id, studentName = s1.name, schoolName = s2.name, areaName = a1.name
}).ToList();
//最多支持5表查询,太过复杂的建议用Sqlable或者SqlQuery,我们的Queryable只适合轻量级的查询
//拼接
var queryable = db.Queryable <Student>().Where(it => true);
if (maxId.ObjToInt() == 1)
{
queryable.Where(it => it.id == 1);
}
else
{
queryable.Where(it => it.id == 2);
}
var listJoin = queryable.ToList();
//queryable和SqlSugarClient解耦
var par = new Queryable <Student>().Where(it => it.id == 1);//声名没有connection对象的Queryable
par.DB = db;
var listPar = par.ToList();
}
}
/// <summary>
/// 多表查询
/// </summary>
private void SqlableDemo()
{
using (var db = SugarDao.GetInstance())
{
//---------Sqlable,创建多表查询---------//
//多表查询
List <School> dataList = db.Sqlable()
.From("school", "s")
.Join("student", "st", "st.id", "s.id", JoinType.INNER)
.Join("student", "st2", "st2.id", "st.id", JoinType.LEFT)
.Where("s.id>100 and s.id<@id")
.Where("1=1")//可以多个WHERE
.OrderBy("ID")
.SelectToList <School /*新的Model我这里没有所以写的School*/>("st.*", new { id = 1 });
//多表分页
List <School> dataPageList = db.Sqlable()
.From("school", "s")
.Join("student", "st", "st.id", "s.id", JoinType.INNER)
.Join("student", "st2", "st2.id", "st.id", JoinType.LEFT)
.Where("s.id>100 and s.id<100")
.SelectToPageList <School>("st.*", "s.id", 1, 10);
//多表分页WHERE加子查询
List <School> dataPageList2 = db.Sqlable()
.From("school", "s")
.Join("student", "st", "st.id", "s.id", JoinType.INNER)
.Join("student", "st2", "st2.id", "st.id", JoinType.LEFT)
.Where("s.id>100 and s.id<100 and s.id in (select 1 )" /*这里面写子查询都可以*/)
.SelectToPageList <School>("st.*", "s.id", 1, 10);
//--------转成List Dynmaic 或者 Json-----//
//不分页
var list1 = db.Sqlable().From("student", "s").Join("school", "l", "s.sch_id", "l.id and l.id=@id", JoinType.INNER).SelectToDynamic("*", new { id = 1 });
var list2 = db.Sqlable().From("student", "s").Join("school", "l", "s.sch_id", "l.id and l.id=@id", JoinType.INNER).SelectToJson("*", new { id = 1 });
var list3 = db.Sqlable().From("student", "s").Join("school", "l", "s.sch_id", "l.id and l.id=@id", JoinType.INNER).SelectToDataTable("*", new { id = 1 });
//分页
var list4 = db.Sqlable().From("student", "s").Join("school", "l", "s.sch_id", "l.id and l.id=@id", JoinType.INNER).SelectToPageDynamic("s.*", "l.id", 1, 10, new { id = 1 });
var list5 = db.Sqlable().From("student", "s").Join("school", "l", "s.sch_id", "l.id and l.id=@id", JoinType.INNER).SelectToPageTable("s.*", "l.id", 1, 10, new { id = 1 });
var list6 = db.Sqlable().From("student", "s").Join("school", "l", "s.sch_id", "l.id and l.id=@id", JoinType.INNER).SelectToPageDynamic("s.*", "l.id", 1, 10, new { id = 1 });
//--------拼接-----//
Sqlable sable = db.Sqlable().From <Student>("s").Join <School>("l", "s.sch_id", "l.id", JoinType.INNER);
string name = "a";
int id = 1;
if (!string.IsNullOrEmpty(name))
{
sable = sable.Where("s.name=@name");
}
if (!string.IsNullOrEmpty(name))
{
sable = sable.Where("s.id=@id or s.id=100");
}
if (id > 0)
{
sable = sable.Where("l.id in (select top 10 id from school)");//where加子查询
}
var pars = new { id = id, name = name };
int pageCount = sable.Count(pars);
var list7 = sable.SelectToPageList <Student>("s.*", "l.id desc", 1, 20, pars);
}
}
/// <summary>
/// 单表查询
/// </summary>
private void QueryableDemo()
{
using (var db = SugarDao.GetInstance())
{
//---------Queryable<T>,扩展函数查询---------//
//针对单表或者视图查询
//查询所有
var student = db.Queryable <Student>().ToList();
var studentDynamic = db.Queryable <Student>().ToDynamic();
var studentJson = db.Queryable <Student>().ToJson();
//查询单条
var single = db.Queryable <Student>().Single(c => c.id == 1);
//查询单条没有记录返回空对象
var single2 = db.Queryable <Student>().Where(c => c.id == 1).SingleOrDefault();
//查询第一条
var first = db.Queryable <Student>().Where(c => c.id == 1).First();
var first2 = db.Queryable <Student>().Where(c => c.id == 1).FirstOrDefault();
//取10-20条
var page1 = db.Queryable <Student>().Where(c => c.id > 10).OrderBy("id").Skip(10).Take(20).ToList();
//上一句的简化写法，同样取10-20条
var page2 = db.Queryable <Student>().Where(c => c.id > 10).OrderBy("id").ToPageList(2, 10);
//查询条数
var count = db.Queryable <Student>().Where(c => c.id > 10).Count();
//从第2条开始以后取所有
var skip = db.Queryable <Student>().Where(c => c.id > 10).OrderBy("id").Skip(2).ToList();
//取前2条
var take = db.Queryable <Student>().Where(c => c.id > 10).OrderBy("id").Take(2).ToList();
// Not like
string conval = "a";
var notLike = db.Queryable <Student>().Where(c => !c.name.Contains(conval.ToString())).ToList();
//Like
conval = "三";
var like = db.Queryable <Student>().Where(c => c.name.Contains(conval)).ToList();
// 可以在拉姆达使用 ToString和 Convert,比EF出色的地方
var convert1 = db.Queryable <Student>().Where(c => c.name == "a".ToString()).ToList();
var convert2 = db.Queryable <Student>().Where(c => c.id == Convert.ToInt32("1")).ToList();//
var convert3 = db.Queryable <Student>().Where(c => DateTime.Now > Convert.ToDateTime("2015-1-1")).ToList();
var convert4 = db.Queryable <Student>().Where(c => DateTime.Now > DateTime.Now).ToList();
//支持字符串Where 让你解决，更复杂的查询
var student12 = db.Queryable <Student>().Where(c => "a" == "a").Where("id>100").ToList();
var student13 = db.Queryable <Student>().Where(c => "a" == "a").Where("id>100 and id in( select 1)").ToList();
//存在记录反回true，则否返回false
bool isAny100 = db.Queryable <Student>().Any(c => c.id == 100);
bool isAny1 = db.Queryable <Student>().Any(c => c.id == 1);
int maxId = db.Queryable <Student>().Max <Student, int>("id");
int minId = db.Queryable <Student>().Where(c => c.id > 0).Min <Student, int>("id");
//In
var list1 = db.Queryable <Student>().In("id", "1", "2", "3").ToList();
var list2 = db.Queryable <Student>().In("id", new string[] { "1", "2", "3" }).ToList();
var list3 = db.Queryable <Student>().In("id", new List <string> {
"1", "2", "3"
}).ToList();
var list4 = db.Queryable <Student>().Where(it => it.id < 10).In("id", new List <string> {
"1", "2", "3"
}).ToList();
//分组查询
var list5 = db.Queryable <Student>().Where(c => c.id < 20).GroupBy("sex").Select <Student, SexTotal>("Sex,Count=count(*)").ToList();
//SELECT Sex,Count=count(*) FROM Student WHERE 1=1 AND (id < 20) GROUP BY Sex --生成结果
}
}
/// <summary>
/// 单表查询
/// </summary>
private void QueryableDemo()
{
using (var db = SugarDao.GetInstance())
{
//---------Queryable<T>,扩展函数查询---------//
//针对单表或者视图查询
//查询所有
var student = db.Queryable <Student>().ToList();
var studentDynamic = db.Queryable <Student>().ToDynamic();
var studentJson = db.Queryable <Student>().ToJson();
//查询单条
var single = db.Queryable <Student>().Single(c => c.id == 1);
//查询单条没有记录返回空对象
var single2 = db.Queryable <Student>().Where(c => c.id == 1).SingleOrDefault();
//查询第一条
var first = db.Queryable <Student>().Where(c => c.id == 1).First();
var first2 = db.Queryable <Student>().Where(c => c.id == 1).FirstOrDefault();
//取10-20条
var page1 = db.Queryable <Student>().Where(c => c.id > 10).OrderBy(it => it.id).Skip(10).Take(20).ToList();
//上一句的简化写法，同样取10-20条
var page2 = db.Queryable <Student>().Where(c => c.id > 10).OrderBy(it => it.id).ToPageList(2, 10);
//查询条数
var count = db.Queryable <Student>().Where(c => c.id > 10).Count();
//从第2条开始以后取所有
var skip = db.Queryable <Student>().Where(c => c.id > 10).OrderBy(it => it.id).Skip(2).ToList();
//取前2条
var take = db.Queryable <Student>().Where(c => c.id > 10).OrderBy(it => it.id).Take(2).ToList();
// Not like
string conval = "a";
var notLike = db.Queryable <Student>().Where(c => !c.name.Contains(conval.ToString())).ToList();
//Like
conval = "三";
var like = db.Queryable <Student>().Where(c => c.name.Contains(conval)).ToList();
// 可以在拉姆达使用 ToString和 Convert,比EF出色的地方
var convert1 = db.Queryable <Student>().Where(c => c.name == "a".ToString()).ToList();
var convert2 = db.Queryable <Student>().Where(c => c.id == Convert.ToInt32("1")).ToList();//
var convert3 = db.Queryable <Student>().Where(c => DateTime.Now > Convert.ToDateTime("2015-1-1")).ToList();
var convert4 = db.Queryable <Student>().Where(c => DateTime.Now > DateTime.Now).ToList();
//支持字符串Where 让你解决，更复杂的查询
var student12 = db.Queryable <Student>().Where(c => "a" == "a").Where("id>100").ToList();
var student13 = db.Queryable <Student>().Where(c => "a" == "a").Where("id>100 and id in( select 1)").ToList();
//存在记录反回true，则否返回false
bool isAny100 = db.Queryable <Student>().Any(c => c.id == 100);
bool isAny1 = db.Queryable <Student>().Any(c => c.id == 1);
//获取最大Id
object maxId = db.Queryable <Student>().Max(it => it.id);
int maxId1 = db.Queryable <Student>().Max(it => it.id).ObjToInt(); //拉姆达
int maxId2 = db.Queryable <Student>().Max <Student, int>("id"); //字符串写法
//获取最小
int minId1 = db.Queryable <Student>().Where(c => c.id > 0).Min(it => it.id).ObjToInt(); //拉姆达
int minId2 = db.Queryable <Student>().Where(c => c.id > 0).Min <Student, int>("id"); //字符串写法
//order By
var orderList = db.Queryable <Student>().OrderBy("id desc,name asc").ToList(); //字符串支持多个排序
//可以多个order by表达示
var order2List = db.Queryable <Student>().OrderBy(it => it.name).OrderBy(it => it.id, OrderByType.desc).ToList(); // order by name as ,order by id desc
//In
var intArray = new[] { "5", "2", "3" };
var intList = intArray.ToList();
var list0 = db.Queryable <Student>().In(it => it.id, 1, 2, 3).ToList();
var list1 = db.Queryable <Student>().In(it => it.id, intArray).ToList();
var list2 = db.Queryable <Student>().In("id", intArray).ToList();
var list3 = db.Queryable <Student>().In(it => it.id, intList).ToList();
var list4 = db.Queryable <Student>().In("id", intList).ToList();
//分组查询
var list7 = db.Queryable <Student>().Where(c => c.id < 20).GroupBy(it => it.sex).Select("sex,Count=count(*)").ToDynamic();
var list8 = db.Queryable <Student>().Where(c => c.id < 20).GroupBy(it => it.sex).GroupBy(it => it.id).Select("id,sex,Count=count(*)").ToDynamic();
List <SexTotal> list9 = db.Queryable <Student>().Where(c => c.id < 20).GroupBy(it => it.sex).Select <Student, SexTotal>("Sex,Count=count(*)").ToList();
List <SexTotal> list10 = db.Queryable <Student>().Where(c => c.id < 20).GroupBy("sex").Select <Student, SexTotal>("Sex,Count=count(*)").ToList();
//SELECT Sex,Count=count(*) FROM Student WHERE 1=1 AND (id < 20) GROUP BY Sex --生成结果
}
}