public interface IDbContext : IDisposable
{IDbSession CurrentSession { get; }IQuery<T> Query<T>() where T : new();IEnumerable<T> SqlQuery<T>(string sql, params DbParam[] parameters) where T : new();T Insert<T>(T entity);object Insert<T>(Expression<Func<T>> body);int Update<T>(T entity);int Update<T>(Expression<Func<T, T>> body, Expression<Func<T, bool>> condition);int Delete<T>(T entity);int Delete<T>(Expression<Func<T, bool>> condition);void TrackEntity(object entity);
}

public enum Gender
{Man = 1,Woman
}[TableAttribute("Users")]
public class User
{[Column(IsPrimaryKey = true)][AutoIncrementAttribute]public int Id { get; set; }public string Name { get; set; }public Gender? Gender { get; set; }public int? Age { get; set; }public int? CityId { get; set; }public DateTime? OpTime { get; set; }
}public class City
{[Column(IsPrimaryKey = true)]public int Id { get; set; }public string Name { get; set; }public int ProvinceId { get; set; }
}public class Province
{[Column(IsPrimaryKey = true)]public int Id { get; set; }public string Name { get; set; }
}

View Code

IDbContext context = new MsSqlContext(DbHelper.ConnectionString);

IQuery<User> q = context.Query<User>();

IQuery<User> q = context.Query<User>();
q.Where(a => a.Id > 0).FirstOrDefault();
q.Where(a => a.Id > 0).ToList();
q.Where(a => a.Id > 0).OrderBy(a => a.Age).ToList();
q.Where(a => a.Id > 0).Take(999).OrderBy(a => a.Age).ToList();//分页。避免生成的 sql 语句太长占篇幅，只选取 Id 和 Name 两个字段
q.Where(a => a.Id > 0).OrderBy(a => a.Age).ThenByDesc(a => a.Id).Select(a => new { a.Id, a.Name }).Skip(1).Take(999).ToList();
/** SELECT TOP (999) [T].[Id] AS [Id],[T].[Name] AS [Name] FROM (SELECT [Users].[Id] AS [Id],[Users].[Name] AS [Name],ROW_NUMBER() OVER(ORDER BY [Users].[Age] ASC,[Users].[Id] DESC) AS [ROW_NUMBER_0] FROM [Users] AS [Users] WHERE [Users].[Id] > 0) AS [T] WHERE [T].[ROW_NUMBER_0] > 1*///如果需要多个条件的话
q.Where(a => a.Id > 0).Where(a => a.Name.Contains("lu")).ToList();
/** SELECT [Users].[Id] AS [Id],[Users].[Name] AS [Name],[Users].[Gender] AS [Gender],[Users].[Age] AS [Age],[Users].[CityId] AS [CityId],[Users].[OpTime] AS [OpTime] FROM [Users] AS [Users] WHERE ([Users].[Id] > 0 AND [Users].[Name] LIKE '%' + N'lu' + '%')*///选取指定字段
q.Select(a => new { a.Id, a.Name, a.Age }).ToList();
//或者
q.Select(a => new User() { Id = a.Id, Name = a.Name, Age = a.Age }).ToList();
/** SELECT [Users].[Id] AS [Id],[Users].[Name] AS [Name],[Users].[Age] AS [Age] FROM [Users] AS [Users]*/

MsSqlContext context = new MsSqlContext(DbHelper.ConnectionString);
IQuery<User> users = context.Query<User>();
IQuery<City> cities = context.Query<City>();
IQuery<Province> provinces = context.Query<Province>();IJoiningQuery<User, City> user_city = users.InnerJoin(cities, (user, city) => user.CityId == city.Id);
IJoiningQuery<User, City, Province> user_city_province = user_city.InnerJoin(provinces, (user, city, province) => city.ProvinceId == province.Id);

user_city_province.Select((user, city, province) => new { UserId = user.Id, CityName = city.Name, ProvinceName = province.Name }).Where(a => a.UserId == 1).ToList();
/** SELECT [Users].[Id] AS [UserId],[City].[Name] AS [CityName],[Province].[Name] AS [ProvinceName] FROM [Users] AS [Users] INNER JOIN [City] AS [City] ON [Users].[CityId] = [City].[Id] INNER JOIN [Province] AS [Province] ON [City].[ProvinceId] = [Province].[Id] WHERE [Users].[Id] = 1*/

var view = user_city_province.Select((user, city, province) => new { User = user, City = city, Province = province });

view.Where(a => a.User.Id == 1).ToList();
/** SELECT [Users].[Id] AS [Id],[Users].[Name] AS [Name],[Users].[Gender] AS [Gender],[Users].[Age] AS [Age],[Users].[CityId] AS [CityId],[Users].[OpTime] AS [OpTime],[City].[Id] AS [Id0],[City].[Name] AS [Name0],[City].[ProvinceId] AS [ProvinceId],[Province].[Id] AS [Id1],[Province].[Name] AS [Name1] FROM [Users] AS [Users] INNER JOIN [City] AS [City] ON [Users].[CityId] = [City].[Id] INNER JOIN [Province] AS [Province] ON [City].[ProvinceId] = [Province].[Id] WHERE [Users].[Id] = 1*/

view.Where(a => a.User.Id == 1).Select(a => new { UserId = a.User.Id, CityName = a.City.Name, ProvinceName = a.Province.Name }).ToList();
/** SELECT [Users].[Id] AS [UserId],[City].[Name] AS [CityName],[Province].[Name] AS [ProvinceName] FROM [Users] AS [Users] INNER JOIN [City] AS [City] ON [Users].[CityId] = [City].[Id] INNER JOIN [Province] AS [Province] ON [City].[ProvinceId] = [Province].[Id] WHERE [Users].[Id] = 1*/

IQuery<User> q = context.Query<User>();q.Select(a => DbFunctions.Count()).First();
/** SELECT TOP (1) COUNT(1) AS [C] FROM [Users] AS [Users]*/q.Select(a => new { Count = DbFunctions.Count(), LongCount = DbFunctions.LongCount(), Sum = DbFunctions.Sum(a.Age), Max = DbFunctions.Max(a.Age), Min = DbFunctions.Min(a.Age), Average = DbFunctions.Average(a.Age) }).First();
/** SELECT TOP (1) COUNT(1) AS [Count],COUNT_BIG(1) AS [LongCount],SUM([Users].[Age]) AS [Sum],MAX([Users].[Age]) AS [Max],MIN([Users].[Age]) AS [Min],CAST(AVG([Users].[Age]) AS FLOAT) AS [Average] FROM [Users] AS [Users]*/var count = q.Count();
/** SELECT COUNT(1) AS [C] FROM [Users] AS [Users]*/var longCount = q.LongCount();
/** SELECT COUNT_BIG(1) AS [C] FROM [Users] AS [Users]*/var sum = q.Sum(a => a.Age);
/** SELECT SUM([Users].[Age]) AS [C] FROM [Users] AS [Users]*/var max = q.Max(a => a.Age);
/** SELECT MAX([Users].[Age]) AS [C] FROM [Users] AS [Users]*/var min = q.Min(a => a.Age);
/** SELECT MIN([Users].[Age]) AS [C] FROM [Users] AS [Users]*/var avg = q.Average(a => a.Age);
/** SELECT CAST(AVG([Users].[Age]) AS FLOAT) AS [C] FROM [Users] AS [Users]*/

IQuery<User> q = context.Query<User>();IGroupingQuery<User> g = q.Where(a => a.Id > 0).GroupBy(a => a.Age);
g = g.Having(a => a.Age > 1 && DbFunctions.Count() > 0);g.Select(a => new { a.Age, Count = DbFunctions.Count(), Sum = DbFunctions.Sum(a.Age), Max = DbFunctions.Max(a.Age), Min = DbFunctions.Min(a.Age), Avg = DbFunctions.Average(a.Age) }).ToList();
/** SELECT [Users].[Age] AS [Age],COUNT(1) AS [Count],SUM([Users].[Age]) AS [Sum],MAX([Users].[Age]) AS [Max],MIN([Users].[Age]) AS [Min],CAST(AVG([Users].[Age]) AS FLOAT) AS [Avg] FROM [Users] AS [Users] WHERE [Users].[Id] > 0 GROUP BY [Users].[Age] HAVING ([Users].[Age] > 1 AND COUNT(1) > 0)*/

context.SqlQuery<User>("select Id,Name,Age from Users where Name=@name", DbParam.Create("@name", "lu")).ToList();
context.SqlQuery<int>("select Id from Users").ToList();

select City.*,T.MinAge from City left join (select CityId,Min(Users.Age) as MinAge from Users group by Users.CityId) as T on City.Id=T.CityId

IQuery<User> users = context.Query<User>();
IQuery<City> cities = context.Query<City>();
var gq = users.GroupBy(a => a.CityId).Select(a => new { a.CityId, MinAge = DbFunctions.Min(a.Age) });cities.LeftJoin(gq, (city, g) => city.Id == g.CityId).Select((city, g) => new { City = city, MinAge = g.MinAge }).ToList();
/** SELECT [T].[MinAge] AS [MinAge],[City].[Id] AS [Id],[City].[Name] AS [Name],[City].[ProvinceId] AS [ProvinceId] FROM [City] AS [City] LEFT JOIN (SELECT [Users].[CityId] AS [CityId],MIN([Users].[Age]) AS [MinAge] FROM [Users] AS [Users] GROUP BY [Users].[CityId]) AS [T] ON [City].[Id] = [T].[CityId]*/

IQuery<User> q = context.Query<User>();List<int> ids = new List<int>();
ids.Add(1);
ids.Add(2);
ids.Add(2);string name = "lu";
string nullString = null;
bool b = false;
bool b1 = true;q.Where(a => true).ToList();
q.Where(a => a.Id == 1).ToList();
q.Where(a => a.Id == 1 || a.Id > 1).ToList();
q.Where(a => a.Id == 1 && a.Name == name && a.Name == nullString && a.Id == FeatureTest.ID).ToList();
q.Where(a => ids.Contains(a.Id)).ToList();
q.Where(a => !b == (a.Id > 0)).ToList();
q.Where(a => a.Id > 0).Where(a => a.Id == 1).ToList();
q.Where(a => !(a.Id > 10)).ToList();
q.Where(a => !(a.Name == name)).ToList();
q.Where(a => a.Name != name).ToList();
q.Where(a => a.Name == name).ToList();
q.Where(a => (a.Name == name) == (a.Id > 0)).ToList();
q.Where(a => a.Name == (a.Name ?? name)).ToList();
q.Where(a => (a.Age == null ? 0 : 1) == 1).ToList();//运算操作符
q.Select(a => new
{Add = 1 + 2,Subtract = 2 - 1,Multiply = 2 * 11,Divide = 4 / 2,And = true & false,IntAnd = 1 & 2,Or = true | false,IntOr = 3 | 1,
}).ToList();

View Code

  IQuery<User> q = context.Query<User>();var space = new char[] { ' ' };DateTime startTime = DateTime.Now;DateTime endTime = DateTime.Now.AddDays(1);q.Select(a => new
{Id = a.Id,String_Length = (int?)a.Name.Length,//LEN([Users].[Name])Substring = a.Name.Substring(0),//SUBSTRING([Users].[Name],0 + 1,LEN([Users].[Name]))Substring1 = a.Name.Substring(1),//SUBSTRING([Users].[Name],1 + 1,LEN([Users].[Name]))Substring1_2 = a.Name.Substring(1, 2),//SUBSTRING([Users].[Name],1 + 1,2)ToLower = a.Name.ToLower(),//LOWER([Users].[Name])ToUpper = a.Name.ToUpper(),//UPPER([Users].[Name])IsNullOrEmpty = string.IsNullOrEmpty(a.Name),//太长，不贴了Contains = (bool?)a.Name.Contains("s"),//太长，略Trim = a.Name.Trim(),//RTRIM(LTRIM([Users].[Name]))TrimStart = a.Name.TrimStart(space),//LTRIM([Users].[Name])TrimEnd = a.Name.TrimEnd(space),//RTRIM([Users].[Name])StartsWith = (bool?)a.Name.StartsWith("s"),//太长，略EndsWith = (bool?)a.Name.EndsWith("s"),//太长，略SubtractTotalDays = endTime.Subtract(startTime).TotalDays,//CAST(DATEDIFF(DAY,@P_0,@P_1)SubtractTotalHours = endTime.Subtract(startTime).TotalHours,//CAST(DATEDIFF(HOUR,@P_0,@P_1)SubtractTotalMinutes = endTime.Subtract(startTime).TotalMinutes,//CAST(DATEDIFF(MINUTE,@P_0,@P_1)SubtractTotalSeconds = endTime.Subtract(startTime).TotalSeconds,//CAST(DATEDIFF(SECOND,@P_0,@P_1)SubtractTotalMilliseconds = endTime.Subtract(startTime).TotalMilliseconds,//CAST(DATEDIFF(MILLISECOND,@P_0,@P_1)Now = DateTime.Now,//GETDATE()UtcNow = DateTime.UtcNow,//GETUTCDATE()Today = DateTime.Today,//CAST(GETDATE() AS DATE)Date = DateTime.Now.Date,//CAST(GETDATE() AS DATE)Year = DateTime.Now.Year,//DATEPART(YEAR,GETDATE())Month = DateTime.Now.Month,//DATEPART(MONTH,GETDATE())Day = DateTime.Now.Day,//DATEPART(DAY,GETDATE())Hour = DateTime.Now.Hour,//DATEPART(HOUR,GETDATE())Minute = DateTime.Now.Minute,//DATEPART(MINUTE,GETDATE())Second = DateTime.Now.Second,//DATEPART(SECOND,GETDATE())Millisecond = DateTime.Now.Millisecond,//DATEPART(MILLISECOND,GETDATE())DayOfWeek = DateTime.Now.DayOfWeek,//(DATEPART(WEEKDAY,GETDATE()) - 1)Int_Parse = int.Parse("1"),//CAST(N'1' AS INT)Int16_Parse = Int16.Parse("11"),//CAST(N'11' AS SMALLINT)Long_Parse = long.Parse("2"),//CAST(N'2' AS BIGINT)Double_Parse = double.Parse("3"),//CAST(N'3' AS FLOAT)Float_Parse = float.Parse("4"),//CAST(N'4' AS REAL)Decimal_Parse = decimal.Parse("5"),//CAST(N'5' AS DECIMAL)Guid_Parse = Guid.Parse("D544BC4C-739E-4CD3-A3D3-7BF803FCE179"),//CAST(N'xxx' AS UNIQUEIDENTIFIER) AS [Guid_Parse]Bool_Parse = bool.Parse("1"),//CASE WHEN CAST(N'1' AS BIT) = CAST(1 AS BIT) THEN CAST(1 AS BIT) WHEN NOT (CAST(N'1' AS BIT) = CAST(1 AS BIT)) THEN CAST(0 AS BIT) ELSE NULL END AS [Bool_Parse]DateTime_Parse = DateTime.Parse("1992-1-16"),//CAST(N'1992-1-16' AS DATETIME) AS [DateTime_Parse]B = a.Age == null ? false : a.Age > 1,
}).ToList();

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