- 增加 linq to sql 的查询语法，以及单元测试；

FreeSql.Tests/LinqToSql/SqliteLinqToSqlTests.cs

@@ -0,0 +1,187 @@
+using FreeSql.DataAnnotations;
+using System;
+using System.Linq;
+using Xunit;
+
+namespace FreeSql.Tests.LinqToSql {
+
+
+	class TestLinqToSql {
+		public Guid id { get; set; }
+
+		public string name { get; set; }
+
+		public int click { get; set; } = 10;
+
+		public DateTime createtime { get; set; } = DateTime.Now;
+	}
+	class TestLinqToSqlComment {
+		public Guid id { get; set; }
+
+		public Guid TestLinqToSqlId { get; set; }
+		public TestLinqToSql TEstLinqToSql { get; set; }
+
+		public string text { get; set; }
+		
+		public DateTime createtime { get; set; } = DateTime.Now;
+	}
+
+	public class SqliteLinqToSqlTests {
+
+		[Fact]
+		public void Where() {
+			var item = new TestLinqToSql { name = Guid.NewGuid().ToString() };
+			g.sqlite.Insert<TestLinqToSql>().AppendData(item).ExecuteAffrows();
+
+			var t1 = (from a in g.sqlite.Select<TestLinqToSql>()
+					  where a.id == item.id
+					  select a).ToList();
+			Assert.True(t1.Any());
+			Assert.Equal(item.id, t1[0].id);
+		}
+
+		[Fact]
+		public void Select() {
+			var item = new TestLinqToSql { name = Guid.NewGuid().ToString() };
+			g.sqlite.Insert<TestLinqToSql>().AppendData(item).ExecuteAffrows();
+
+			var t1 = (from a in g.sqlite.Select<TestLinqToSql>()
+					  where a.id == item.id
+					  select new { a.id }).ToList();
+			Assert.True(t1.Any());
+			Assert.Equal(item.id, t1[0].id);
+		}
+
+		[Fact]
+		public void GroupBy() {
+			var item = new TestLinqToSql { name = Guid.NewGuid().ToString() };
+			g.sqlite.Insert<TestLinqToSql>().AppendData(item).ExecuteAffrows();
+
+			var t1 = (from a in g.sqlite.Select<TestLinqToSql>()
+					 where a.id == item.id
+					 group a by new {a.id, a.name } into g
+					 select new {
+						 g.Key.id, g.Key.name,
+						 cou = g.Count(),
+						 avg = g.Avg(g.Value.click),
+						 sum = g.Sum(g.Value.click),
+						 max = g.Max(g.Value.click),
+						 min = g.Min(g.Value.click)
+					 }).ToList();
+			Assert.True(t1.Any());
+			Assert.Equal(item.id, t1.First().id);
+		}
+
+		[Fact]
+		public void CaseWhen() {
+			var item = new TestLinqToSql { name = Guid.NewGuid().ToString() };
+			g.sqlite.Insert<TestLinqToSql>().AppendData(item).ExecuteAffrows();
+
+			var t1 = (from a in g.sqlite.Select<TestLinqToSql>()
+					 where a.id == item.id
+					 select new {
+						 a.id,
+						 a.name,
+						 testsub = new {
+							time = a.click > 10 ? "大于" : "小于或等于"
+						 }
+					 }).ToList();
+			Assert.True(t1.Any());
+			Assert.Equal(item.id, t1[0].id);
+			Assert.Equal("小于或等于", t1[0].testsub.time);
+		}
+
+		[Fact]
+		public void Join() {
+			var item = new TestLinqToSql { name = Guid.NewGuid().ToString() };
+			g.sqlite.Insert<TestLinqToSql>().AppendData(item).ExecuteAffrows();
+			var comment = new TestLinqToSqlComment { TestLinqToSqlId = item.id, text = Guid.NewGuid().ToString() };
+			g.sqlite.Insert<TestLinqToSqlComment>().AppendData(comment).ExecuteAffrows();
+
+			var t1 = (from a in g.sqlite.Select<TestLinqToSql>()
+					 join b in g.sqlite.Select<TestLinqToSqlComment>() on a.id equals b.TestLinqToSqlId
+					 select a).ToList();
+			Assert.True(t1.Any());
+			//Assert.Equal(item.id, t1[0].id);
+
+			var t2 = (from a in g.sqlite.Select<TestLinqToSql>()
+					 join b in g.sqlite.Select<TestLinqToSqlComment>() on a.id equals b.TestLinqToSqlId
+					 select new { a.id, bid = b.id }).ToList();
+			Assert.True(t2.Any());
+			//Assert.Equal(item.id, t2[0].id);
+			//Assert.Equal(comment.id, t2[0].bid);
+
+			var t3 = (from a in g.sqlite.Select<TestLinqToSql>()
+					 join b in g.sqlite.Select<TestLinqToSqlComment>() on a.id equals b.TestLinqToSqlId
+					 where a.id == item.id
+					 select new { a.id, bid = b.id }).ToList();
+			Assert.True(t3.Any());
+			Assert.Equal(item.id, t3[0].id);
+			Assert.Equal(comment.id, t3[0].bid);
+		}
+
+		[Fact]
+		public void LeftJoin() {
+			var item = new TestLinqToSql { name = Guid.NewGuid().ToString() };
+			g.sqlite.Insert<TestLinqToSql>().AppendData(item).ExecuteAffrows();
+			var comment = new TestLinqToSqlComment { TestLinqToSqlId = item.id, text = Guid.NewGuid().ToString() };
+			g.sqlite.Insert<TestLinqToSqlComment>().AppendData(comment).ExecuteAffrows();
+
+			var t1 = (from a in g.sqlite.Select<TestLinqToSql>()
+					  join b in g.sqlite.Select<TestLinqToSqlComment>() on a.id equals b.TestLinqToSqlId into temp
+					  from tc in temp.DefaultIfEmpty()
+					  select a).ToList();
+			Assert.True(t1.Any());
+			//Assert.Equal(item.id, t1[0].id);
+
+			var t2 = (from a in g.sqlite.Select<TestLinqToSql>()
+					  join b in g.sqlite.Select<TestLinqToSqlComment>() on a.id equals b.TestLinqToSqlId into temp
+					  from tc in temp.DefaultIfEmpty()
+					  select new { a.id, bid = tc.id }).ToList();
+			Assert.True(t2.Any());
+			//Assert.Equal(item.id, t2[0].id);
+			//Assert.Equal(comment.id, t2[0].bid);
+
+			var t3 = (from a in g.sqlite.Select<TestLinqToSql>()
+					  join b in g.sqlite.Select<TestLinqToSqlComment>() on a.id equals b.TestLinqToSqlId into temp
+					  from tc in temp.DefaultIfEmpty()
+					  where a.id == item.id
+					  select new { a.id, bid = tc.id }).ToList();
+			Assert.True(t3.Any());
+			Assert.Equal(item.id, t3[0].id);
+			Assert.Equal(comment.id, t3[0].bid);
+		}
+
+		[Fact]
+		public void From() {
+			var item = new TestLinqToSql { name = Guid.NewGuid().ToString() };
+			g.sqlite.Insert<TestLinqToSql>().AppendData(item).ExecuteAffrows();
+			var comment = new TestLinqToSqlComment { TestLinqToSqlId = item.id, text = Guid.NewGuid().ToString() };
+			g.sqlite.Insert<TestLinqToSqlComment>().AppendData(comment).ExecuteAffrows();
+
+			var t1 = (from a in g.sqlite.Select<TestLinqToSql>()
+					  from b in g.sqlite.Select<TestLinqToSqlComment>()
+					  where a.id == b.TestLinqToSqlId
+					  select a).ToList();
+			Assert.True(t1.Any());
+			//Assert.Equal(item.id, t1[0].id);
+
+			var t2 = (from a in g.sqlite.Select<TestLinqToSql>()
+					  from b in g.sqlite.Select<TestLinqToSqlComment>()
+					  where a.id == b.TestLinqToSqlId
+					  select new { a.id, bid = b.id }).ToList();
+			Assert.True(t2.Any());
+			//Assert.Equal(item.id, t2[0].id);
+			//Assert.Equal(comment.id, t2[0].bid);
+
+			var t3 = (from a in g.sqlite.Select<TestLinqToSql>()
+					  from b in g.sqlite.Select<TestLinqToSqlComment>()
+					  where a.id == b.TestLinqToSqlId
+					  where a.id == item.id
+					  select new { a.id, bid = b.id }).ToList();
+			Assert.True(t3.Any());
+			Assert.Equal(item.id, t3[0].id);
+			Assert.Equal(comment.id, t3[0].bid);
+		}
+	}
+}

FreeSql.Tests/UnitTest1.cs

@@ -88,6 +88,18 @@ namespace FreeSql.Tests {
 
 		[Fact]
 		public void Test1() {
+			var linqto1 = 
+				from p in g.sqlite.Select<Order>()
+				where p.Id >= 0
+				// && p.OrderDetails.AsSelect().Where(c => c.Id > 10).Any()
+				orderby p.Id descending
+				orderby p.CustomerName ascending
+				select new { Name = p.CustomerName, Length = p.Id };
+
+
+
+
+
 
 			var testddd = new TestEntity {
 				Test = 22,

FreeSql/Extensions/FreeSqlGlobalExtensions.cs

@@ -27,6 +27,7 @@ public static class FreeSqlGlobalExtensions {
 	});
 	public static bool IsNumberType(this Type that) => that == null ? false : dicIsNumberType.Value.ContainsKey(that);
 	public static bool IsNullableType(this Type that) => that?.FullName.StartsWith("System.Nullable`1[") == true;
+	public static bool IsAnonymousType(this Type that) => that?.FullName.StartsWith("<>f__AnonymousType") == true;
 	internal static Type NullableTypeOrThis(this Type that) => that?.IsNullableType() == true ? that.GenericTypeArguments.First() : that;
 
 	/// <summary>

FreeSql/FreeSql.csproj

@@ -2,7 +2,7 @@
 
 	<PropertyGroup>
 		<TargetFramework>netstandard2.0</TargetFramework>
-		<Version>0.5.8</Version>
+		<Version>0.5.9</Version>
 		<GeneratePackageOnBuild>true</GeneratePackageOnBuild>
 		<Authors>YeXiangQin</Authors>
 		<Description>FreeSql is the most convenient ORM in dotnet. It supports Mysql, Postgresql, SqlServer, Oracle and Sqlite.</Description>

FreeSql/FreeSql.xml

@@ -963,6 +963,31 @@
             <param name="select">选择列</param>
             <returns></returns>
         </member>
+        <member name="M:FreeSql.ISelect`1.Select``1(System.Linq.Expressions.Expression{System.Func{`0,``0}})">
+            <summary>
+            【linq to sql】专用方法，不建议直接使用
+            </summary>
+        </member>
+        <member name="M:FreeSql.ISelect`1.Join``3(FreeSql.ISelect{``0},System.Linq.Expressions.Expression{System.Func{`0,``1}},System.Linq.Expressions.Expression{System.Func{``0,``1}},System.Linq.Expressions.Expression{System.Func{`0,``0,``2}})">
+            <summary>
+            【linq to sql】专用方法，不建议直接使用
+            </summary>
+        </member>
+        <member name="M:FreeSql.ISelect`1.GroupJoin``3(FreeSql.ISelect{``0},System.Linq.Expressions.Expression{System.Func{`0,``1}},System.Linq.Expressions.Expression{System.Func{``0,``1}},System.Linq.Expressions.Expression{System.Func{`0,FreeSql.ISelect{``0},``2}})">
+            <summary>
+            【linq to sql】专用方法，不建议直接使用
+            </summary>
+        </member>
+        <member name="M:FreeSql.ISelect`1.DefaultIfEmpty">
+            <summary>
+            【linq to sql】专用方法，不建议直接使用
+            </summary>
+        </member>
+        <member name="M:FreeSql.ISelect`1.SelectMany``2(System.Linq.Expressions.Expression{System.Func{`0,FreeSql.ISelect{``0}}},System.Linq.Expressions.Expression{System.Func{`0,``0,``1}})">
+            <summary>
+            【linq to sql】专用方法，不建议直接使用
+            </summary>
+        </member>
         <member name="M:FreeSql.ISelect`1.ToOne``1(System.Linq.Expressions.Expression{System.Func{`0,``0}})">
             <summary>
             执行SQL查询，返回指定字段的记录的第一条记录，记录不存在时返回 TReturn 默认值
@@ -1291,6 +1316,11 @@
             <param name="select">选择列</param>
             <returns></returns>
         </member>
+        <member name="M:FreeSql.ISelectGrouping`2.Select``1(System.Linq.Expressions.Expression{System.Func{FreeSql.ISelectGroupingAggregate{`0,`1},``0}})">
+            <summary>
+            【linq to sql】专用方法，不建议直接使用
+            </summary>
+        </member>
         <member name="M:FreeSql.ISelectGrouping`2.ToSql``1(System.Linq.Expressions.Expression{System.Func{FreeSql.ISelectGroupingAggregate{`0,`1},``0}})">
             <summary>
             返回即将执行的SQL语句

FreeSql/Interface/Curd/ISelect/ISelect1.cs

@@ -31,6 +31,27 @@ namespace FreeSql {
 		List<TReturn> ToList<TReturn>(Expression<Func<T1, TReturn>> select);
 		Task<List<TReturn>> ToListAsync<TReturn>(Expression<Func<T1, TReturn>> select);
 
+		/// <summary>
+		/// 【linq to sql】专用方法，不建议直接使用
+		/// </summary>
+		ISelect<TReturn> Select<TReturn>(Expression<Func<T1, TReturn>> select) where TReturn : class;
+		/// <summary>
+		/// 【linq to sql】专用方法，不建议直接使用
+		/// </summary>
+		ISelect<TResult> Join<TInner, TKey, TResult>(ISelect<TInner> inner, Expression<Func<T1, TKey>> outerKeySelector, Expression<Func<TInner, TKey>> innerKeySelector, Expression<Func<T1, TInner, TResult>> resultSelector) where TInner : class where TResult : class;
+		/// <summary>
+		/// 【linq to sql】专用方法，不建议直接使用
+		/// </summary>
+		ISelect<TResult> GroupJoin<TInner, TKey, TResult>(ISelect<TInner> inner, Expression<Func<T1, TKey>> outerKeySelector, Expression<Func<TInner, TKey>> innerKeySelector, Expression<Func<T1, ISelect<TInner>, TResult>> resultSelector) where TInner : class where TResult : class;
+		/// <summary>
+		/// 【linq to sql】专用方法，不建议直接使用
+		/// </summary>
+		ISelect<T1> DefaultIfEmpty();
+		/// <summary>
+		/// 【linq to sql】专用方法，不建议直接使用
+		/// </summary>
+		ISelect<TResult> SelectMany<TCollection, TResult>(Expression<Func<T1, ISelect<TCollection>>> collectionSelector, Expression<Func<T1, TCollection, TResult>> resultSelector) where TCollection : class where TResult : class;
+		
 		/// <summary>
 		/// 执行SQL查询，返回指定字段的记录的第一条记录，记录不存在时返回 TReturn 默认值
 		/// </summary>

FreeSql/Interface/Curd/ISelect/ISelectGrouping.cs

@@ -36,6 +36,11 @@ namespace FreeSql {
 		List<TReturn> ToList<TReturn>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>> select);
 		Task<List<TReturn>> ToListAsync<TReturn>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>> select);
 
+		/// <summary>
+		/// 【linq to sql】专用方法，不建议直接使用
+		/// </summary>
+		List<TReturn> Select<TReturn>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>> select);
+
 		/// <summary>
 		/// 返回即将执行的SQL语句
 		/// </summary>

FreeSql/Internal/CommonExpression.cs

@@ -770,7 +770,7 @@ namespace FreeSql.Internal {
 							if (mp?.Expression != null) { //导航条件，OneToOne、ManyToOne
 								var firstTb = tsc._tables.First().Table;
 								var parentTb = _common.GetTableByEntity(mp.Expression.Type);
-								var parentTbRef = parentTb.GetTableRef(mp.Member.Name, tsc.style == ExpressionStyle.AsSelect);
+								var parentTbRef = parentTb?.GetTableRef(mp.Member.Name, tsc.style == ExpressionStyle.AsSelect);
 								if (parentTbRef != null) {
 									Expression navCondExp = null;
 									for (var mn = 0; mn < parentTbRef.Columns.Count; mn++) {

FreeSql/Internal/CommonProvider/SelectProvider/Select0Provider.cs

@@ -31,6 +31,7 @@ namespace FreeSql.Internal.CommonProvider {
 		protected DbConnection _connection;
 		protected Action<object> _trackToList;
 		protected bool _distinct;
+		protected Expression _selectExpression;
 
 		internal static void CopyData(Select0Provider<TSelect, T1> from, object to, ReadOnlyCollection<ParameterExpression> lambParms) {
 			var toType = to?.GetType();
@@ -43,19 +44,22 @@ namespace FreeSql.Internal.CommonProvider {
 			toType.GetField("_having", BindingFlags.Instance | BindingFlags.NonPublic)?.SetValue(to, from._having);
 			toType.GetField("_where", BindingFlags.Instance | BindingFlags.NonPublic)?.SetValue(to, new StringBuilder().Append(from._where.ToString()));
 			toType.GetField("_params", BindingFlags.Instance | BindingFlags.NonPublic)?.SetValue(to, new List<DbParameter>(from._params.ToArray()));
-			//toType.GetField("_tables", BindingFlags.Instance | BindingFlags.NonPublic)?.SetValue(to, new List<SelectTableInfo>(from._tables.ToArray()));
+			if (lambParms == null)
-			var _multiTables = toType.GetField("_tables", BindingFlags.Instance | BindingFlags.NonPublic).GetValue(to) as List<SelectTableInfo>;
+				toType.GetField("_tables", BindingFlags.Instance | BindingFlags.NonPublic)?.SetValue(to, new List<SelectTableInfo>(from._tables.ToArray()));
-			_multiTables[0] = from._tables[0];
+			else {
-			for (var a = 1; a < lambParms.Count; a++) {
+				var _multiTables = toType.GetField("_tables", BindingFlags.Instance | BindingFlags.NonPublic).GetValue(to) as List<SelectTableInfo>;
-				var tb = from._tables.Where(b => b.Alias == lambParms[a].Name && b.Table.Type == lambParms[a].Type).FirstOrDefault();
+				_multiTables[0] = from._tables[0];
-				if (tb != null) _multiTables[a] = tb;
+				for (var a = 1; a < lambParms.Count; a++) {
-				else {
+					var tb = from._tables.Where(b => b.Alias == lambParms[a].Name && b.Table.Type == lambParms[a].Type).FirstOrDefault();
-					_multiTables[a].Alias = lambParms[a].Name;
+					if (tb != null) _multiTables[a] = tb;
-					_multiTables[a].Parameter = lambParms[a];
+					else {
+						_multiTables[a].Alias = lambParms[a].Name;
+						_multiTables[a].Parameter = lambParms[a];
+					}
 				}
+				if (_multiTables.Count < from._tables.Count)
+					_multiTables.AddRange(from._tables.GetRange(_multiTables.Count, from._tables.Count - _multiTables.Count));
 			}
-			if (_multiTables.Count < from._tables.Count)
-				_multiTables.AddRange(from._tables.GetRange(_multiTables.Count, from._tables.Count - _multiTables.Count));
 			toType.GetField("_tableRules", BindingFlags.Instance | BindingFlags.NonPublic)?.SetValue(to, from._tableRules);
 			toType.GetField("_join", BindingFlags.Instance | BindingFlags.NonPublic)?.SetValue(to, new StringBuilder().Append(from._join.ToString()));
 			toType.GetField("_cache", BindingFlags.Instance | BindingFlags.NonPublic)?.SetValue(to, from._cache);
@@ -66,6 +70,7 @@ namespace FreeSql.Internal.CommonProvider {
 			toType.GetField("_connection", BindingFlags.Instance | BindingFlags.NonPublic)?.SetValue(to, from._connection);
 			toType.GetField("_trackToList", BindingFlags.Instance | BindingFlags.NonPublic)?.SetValue(to, from._trackToList);
 			toType.GetField("_distinct", BindingFlags.Instance | BindingFlags.NonPublic)?.SetValue(to, from._distinct);
+			toType.GetField("_selectExpression", BindingFlags.Instance | BindingFlags.NonPublic)?.SetValue(to, from._selectExpression);
 		}
 
 		public Select0Provider(IFreeSql orm, CommonUtils commonUtils, CommonExpression commonExpression, object dywhere) {
@@ -366,10 +371,14 @@ namespace FreeSql.Internal.CommonProvider {
 				return ret;
 			});
 		}
-		public List<T1> ToList(bool includeNestedMembers = false) => 
+		public List<T1> ToList(bool includeNestedMembers = false) {
-			this.ToListPrivate(includeNestedMembers == false ? this.GetAllFieldExpressionTreeLevel2() : this.GetAllFieldExpressionTreeLevelAll());
+			if (_selectExpression != null) return this.InternalToList<T1>(_selectExpression);
-		public Task<List<T1>> ToListAsync(bool includeNestedMembers = false) => 
+			return this.ToListPrivate(includeNestedMembers == false ? this.GetAllFieldExpressionTreeLevel2() : this.GetAllFieldExpressionTreeLevelAll());
-			this.ToListPrivateAsync(includeNestedMembers == false ? this.GetAllFieldExpressionTreeLevel2() : this.GetAllFieldExpressionTreeLevelAll());
+		}
+		public Task<List<T1>> ToListAsync(bool includeNestedMembers = false) {
+			if (_selectExpression != null) return this.InternalToListAsync<T1>(_selectExpression);
+			return this.ToListPrivateAsync(includeNestedMembers == false ? this.GetAllFieldExpressionTreeLevel2() : this.GetAllFieldExpressionTreeLevelAll());
+		}
 		public T1 ToOne() {
 			this.Limit(1);
 			return this.ToList().FirstOrDefault();

FreeSql/Internal/CommonProvider/SelectProvider/Select1Provider.cs

@@ -5,6 +5,7 @@ using System.Data;
 using System.Linq;
 using System.Linq.Expressions;
 using System.Text;
+using System.Text.RegularExpressions;
 using System.Threading.Tasks;
 
 namespace FreeSql.Internal.CommonProvider {
@@ -153,6 +154,70 @@ namespace FreeSql.Internal.CommonProvider {
 			return this.InternalToListAsync<TReturn>(select?.Body);
 		}
 
+		public ISelect<TReturn> Select<TReturn>(Expression<Func<T1, TReturn>> select) where TReturn : class {
+			if (typeof(TReturn) == typeof(T1)) return this as ISelect<TReturn>;
+			_tables[0].Parameter = select.Parameters[0];
+			_selectExpression = select.Body;
+			var ret = _orm.Select<TReturn>();
+			Select0Provider<ISelect<T1>, T1>.CopyData(this, ret, null);
+			return ret;
+		}
+		public ISelect<TResult> Join<TInner, TKey, TResult>(ISelect<TInner> inner, Expression<Func<T1, TKey>> outerKeySelector, Expression<Func<TInner, TKey>> innerKeySelector, Expression<Func<T1, TInner, TResult>> resultSelector) where TInner : class where TResult : class {
+			_tables[0].Parameter = resultSelector.Parameters[0];
+			_commonExpression.ExpressionLambdaToSql(outerKeySelector, new CommonExpression.ExpTSC { _tables = _tables });
+			this.InternalJoin(Expression.Lambda<Func<T1, TInner, bool>>(
+				Expression.Equal(outerKeySelector.Body, innerKeySelector.Body), 
+				new[] { outerKeySelector.Parameters[0], innerKeySelector.Parameters[0] }
+			), SelectTableInfoType.InnerJoin);
+			if (typeof(TResult) == typeof(T1)) return this as ISelect<TResult>;
+			_selectExpression = resultSelector.Body;
+			var ret = _orm.Select<TResult>() as Select1Provider<TResult>;
+			Select0Provider<ISelect<T1>, T1>.CopyData(this, ret, null);
+			return ret;
+		}
+		public ISelect<TResult> GroupJoin<TInner, TKey, TResult>(ISelect<TInner> inner, Expression<Func<T1, TKey>> outerKeySelector, Expression<Func<TInner, TKey>> innerKeySelector, Expression<Func<T1, ISelect<TInner>, TResult>> resultSelector) where TInner : class where TResult : class {
+			_tables[0].Parameter = resultSelector.Parameters[0];
+			_commonExpression.ExpressionLambdaToSql(outerKeySelector, new CommonExpression.ExpTSC { _tables = _tables });
+			this.InternalJoin(Expression.Lambda<Func<T1, TInner, bool>>(
+				Expression.Equal(outerKeySelector.Body, innerKeySelector.Body),
+				new[] { outerKeySelector.Parameters[0], innerKeySelector.Parameters[0] }
+			), SelectTableInfoType.InnerJoin);
+			if (typeof(TResult) == typeof(T1)) return this as ISelect<TResult>;
+			_selectExpression = resultSelector.Body;
+			var ret = _orm.Select<TResult>() as Select1Provider<TResult>;
+			Select0Provider<ISelect<T1>, T1>.CopyData(this, ret, null);
+			return ret;
+		}
+		public ISelect<TResult> SelectMany<TCollection, TResult>(Expression<Func<T1, ISelect<TCollection>>> collectionSelector, Expression<Func<T1, TCollection, TResult>> resultSelector) where TCollection : class where TResult : class {
+			SelectTableInfo find = null;
+			if (collectionSelector.Body.NodeType == ExpressionType.Call) {
+				var callExp = collectionSelector.Body as MethodCallExpression;
+				if (callExp.Method.Name == "DefaultIfEmpty" && callExp.Object.Type.GenericTypeArguments.Any()) {
+					find = _tables.Where((a, idx) => idx > 0 && a.Type == SelectTableInfoType.InnerJoin && a.Table.Type == callExp.Object.Type.GenericTypeArguments[0]).LastOrDefault();
+					if (find != null) {
+						if (!string.IsNullOrEmpty(find.On)) find.On = Regex.Replace(find.On, $@"\b{find.Alias}\.", $"{resultSelector.Parameters[1].Name}.");
+						if (!string.IsNullOrEmpty(find.NavigateCondition)) find.NavigateCondition = Regex.Replace(find.NavigateCondition, $@"\b{find.Alias}\.", $"{resultSelector.Parameters[1].Name}.");
+						find.Type = SelectTableInfoType.LeftJoin;
+						find.Alias = resultSelector.Parameters[1].Name;
+						find.Parameter = resultSelector.Parameters[1];
+					}
+				}
+			}
+			if (find == null) {
+				var tb = _commonUtils.GetTableByEntity(typeof(TCollection));
+				if (tb == null) throw new Exception($"SelectMany 错误的类型：{typeof(TCollection).FullName}");
+				_tables.Add(new SelectTableInfo { Alias = resultSelector.Parameters[1].Name, AliasInit = resultSelector.Parameters[1].Name, Parameter = resultSelector.Parameters[1], Table = tb, Type = SelectTableInfoType.From });
+			}
+			if (typeof(TResult) == typeof(T1)) return this as ISelect<TResult>;
+			_selectExpression = resultSelector.Body;
+			var ret = _orm.Select<TResult>() as Select1Provider<TResult>;
+			Select0Provider<ISelect<T1>, T1>.CopyData(this, ret, null);
+			return ret;
+		}
+		public ISelect<T1> DefaultIfEmpty() {
+			return this;
+		}
+
 		public DataTable ToDataTable<TReturn>(Expression<Func<T1, TReturn>> select) {
 			if (select == null) return this.InternalToDataTable(select?.Body);
 			_tables[0].Parameter = select.Parameters[0];

FreeSql/Internal/CommonProvider/SelectProvider/SelectGroupingProvider.cs

@@ -110,6 +110,7 @@ namespace FreeSql.Internal.CommonProvider {
 			method = method.MakeGenericMethod(typeof(TReturn));
 			return method.Invoke(_select, new object[] { (map, field.Length > 0 ? field.Remove(0, 2).ToString() : null) }) as Task<List<TReturn>>;
 		}
+		public List<TReturn> Select<TReturn>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>> select) => ToList(select);
 
 		public string ToSql<TReturn>(Expression<Func<ISelectGroupingAggregate<TKey, TValue>, TReturn>> select) {
 			var map = new ReadAnonymousTypeInfo();

FreeSql/Internal/UtilsExpressionTree.cs

@@ -18,7 +18,7 @@ namespace FreeSql.Internal {
 
 		static ConcurrentDictionary<DataType, ConcurrentDictionary<Type, TableInfo>> _cacheGetTableByEntity = new ConcurrentDictionary<DataType, ConcurrentDictionary<Type, TableInfo>>();
 		internal static void RemoveTableByEntity(Type entity, CommonUtils common) {
-			if (entity.FullName.StartsWith("<>f__AnonymousType") ||
+			if (entity.IsAnonymousType() ||
 				entity.IsValueType ||
 				entity.IsNullableType() ||
 				entity.NullableTypeOrThis() == typeof(BigInteger)
@@ -27,7 +27,7 @@ namespace FreeSql.Internal {
 			if (tbc.TryRemove(entity, out var trytb) && trytb?.TypeLazy != null) tbc.TryRemove(trytb.TypeLazy, out var trylz);
 		}
 		internal static TableInfo GetTableByEntity(Type entity, CommonUtils common) {
-			if (entity.FullName.StartsWith("<>f__AnonymousType") ||
+			if (entity.IsAnonymousType() ||
 				entity.IsValueType || 
 				entity.IsNullableType() || 
 				entity.NullableTypeOrThis() == typeof(BigInteger)

FreeSql/Sqlite/SqliteCodeFirst.cs

@@ -254,7 +254,7 @@ namespace FreeSql.Sqlite {
 		public bool SyncStructure<TEntity>() => this.SyncStructure(typeof(TEntity));
 		public bool SyncStructure(params Type[] entityTypes) {
 			if (entityTypes == null) return true;
-			var syncTypes = entityTypes.Where(a => dicSyced.ContainsKey(a.FullName) == false).ToArray();
+			var syncTypes = entityTypes.Where(a => a.IsAnonymousType() == false && dicSyced.ContainsKey(a.FullName) == false).ToArray();
 			if (syncTypes.Any() == false) return true;
 			var before = new Aop.SyncStructureBeforeEventArgs(entityTypes);
 			_orm.Aop.SyncStructureBefore?.Invoke(this, before);