优化sum和average的代码并且修复average的计算类型不一致bug

Author: xuejmnet

samples/Sample.SqlServer/Controllers/ValuesController.cs

@@ -105,6 +105,8 @@ on ut.UserId equals u.Id
             }
             //_defaultTableDbContext.RemoveRange(_defaultTableDbContext.Set<SysUserMod>());
             //await _defaultTableDbContext.SaveChangesAsync();
+
+            var sresultx1121222 = await _defaultTableDbContext.Set<SysUserMod>().Where(o => o.Id == "198").MaxAsync(o => o.Age);
             return Ok();
         }
         [HttpGet]

src/ShardingCore/Extensions/TypeExtension.cs

@@ -0,0 +1,71 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ShardingCore.Extensions
+{
+    internal static class TypeExtension
+    {
+        /// <summary>
+        /// 判断类型是否是可为空类型
+        /// </summary>
+        /// <param name="type"></param>
+        /// <returns></returns>
+        public static bool IsNullableType(this Type type)
+        {
+            return !type.IsValueType || (Nullable.GetUnderlyingType(type) != null);
+        }
+        /// <summary>
+        /// 检测是否是数字类型,包括nullable的数字类型
+        /// </summary>
+        /// <remarks>
+        /// bool 不是数字类型
+        /// </remarks>
+        public static bool IsNumericType(this Type type)
+        {
+            if (type == null)
+            {
+                return false;
+            }
+
+            switch (Type.GetTypeCode(type))
+            {
+                case TypeCode.Byte:
+                case TypeCode.Decimal:
+                case TypeCode.Double:
+                case TypeCode.Int16:
+                case TypeCode.Int32:
+                case TypeCode.Int64:
+                case TypeCode.SByte:
+                case TypeCode.Single:
+                case TypeCode.UInt16:
+                case TypeCode.UInt32:
+                case TypeCode.UInt64:
+                    return true;
+                case TypeCode.Object:
+                    if (type.IsGenericType && type.GetGenericTypeDefinition() == typeof(Nullable<>))
+                    {
+                        return IsNumericType(Nullable.GetUnderlyingType(type));
+                    }
+                    return false;
+            }
+            return false;
+        }
+        /// <summary>
+        /// 是否是bool类型
+        /// </summary>
+        /// <param name="type"></param>
+        /// <returns></returns>
+        public static bool IsBooleanType(Type type)
+        {
+            if (type == null)
+            {
+                return false;
+            }
+
+            return Type.GetTypeCode(type) == TypeCode.Boolean;
+        }
+    }
+}

src/ShardingCore/Sharding/Enumerators/AggregateExtensions/AggregateExtension.cs

@@ -4,6 +4,7 @@
 using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
+using ShardingCore.Exceptions;
 using ShardingCore.Extensions;
 
 namespace ShardingCore.Sharding.Enumerators.AggregateExtensions
@@ -98,11 +99,20 @@ public static object Count(this IQueryable source, string propertyName)
 
             return source.Count(property);
         }
-        public static object Sum(this IQueryable source, PropertyInfo property)
+        /// <summary>
+        /// 根据属性求和
+        /// </summary>
+        /// <param name="source"></param>
+        /// <param name="property"></param>
+        /// <returns></returns>
+        /// <exception cref="ArgumentNullException"></exception>
+        public static object SumByProperty(this IQueryable source, PropertyInfo property)
         {
             if (source == null) throw new ArgumentNullException(nameof(source));
             if (property == null) throw new ArgumentNullException(nameof(property));
-
+            if (!property.PropertyType.IsNumericType())
+                throw new ShardingCoreInvalidOperationException(
+                    $"method sum cant calc type :[{property.PropertyType}]");
             ParameterExpression parameter = Expression.Parameter(source.ElementType, "s");
             MemberExpression getter = Expression.MakeMemberAccess(parameter, property);
             Expression selector = Expression.Lambda(getter, parameter);
@@ -120,14 +130,20 @@ public static object Sum(this IQueryable source, PropertyInfo property)
 
             return source.Provider.Execute(callExpression);
         }
-        [ExcludeFromCodeCoverage]
-        public static object Sum(this IQueryable source, string propertyName)
+        /// <summary>
+        /// 根据属性求和
+        /// </summary>
+        /// <param name="source"></param>
+        /// <param name="propertyName"></param>
+        /// <returns></returns>
+        /// <exception cref="ArgumentNullException"></exception>
+        public static object SumByPropertyName(this IQueryable source, string propertyName)
         {
             if (source == null) throw new ArgumentNullException(nameof(source));
             if (propertyName == null) throw new ArgumentNullException(nameof(propertyName));
 
             PropertyInfo property = source.ElementType.GetProperty(propertyName);
-            return source.Sum(property);
+            return source.SumByProperty(property);
         }
         //public static object Average(this IQueryable source, string member)
         //{
@@ -160,7 +176,7 @@ public static object Sum(this IQueryable source, string propertyName)
         //             && m.IsGenericMethod);
 
         //    // Now that we have the correct method, we need to know how to call the method.
-        //    // Note that the Queryable.Sum<TSource>(source, selector) has a generic type,
+        //    // Note that the Queryable.SumByProperty<TSource>(source, selector) has a generic type,
         //    // which we haven't resolved yet. Good thing is that we can use copy the one from
         //    // our initial source expression.
         //    var genericAvgMethod = avgMethod.MakeGenericMethod(new[] {source.ElementType});
@@ -253,28 +269,46 @@ public static object Min(this IQueryable source, PropertyInfo property)
         /// <param name="source">数据源</param>
         /// <param name="averagePropertyName">聚合函数average属性名</param>
         /// <param name="countPropertyName">聚合函数count属性名</param>
+        /// <param name="resultType">平均值返回结果:int/int=double</param>
         [ExcludeFromCodeCoverage]
-        public static object AverageWithCount(this IQueryable source, string averagePropertyName, string countPropertyName)
+        public static object AverageWithCount(this IQueryable source, string averagePropertyName, string countPropertyName, Type resultType)
         {
             if (source == null) throw new ArgumentNullException(nameof(source));
             if (averagePropertyName == null) throw new ArgumentNullException(nameof(averagePropertyName));
             if (countPropertyName == null) throw new ArgumentNullException(nameof(countPropertyName));
             var averageProperty = source.ElementType.GetProperty(averagePropertyName);
             var countProperty = source.ElementType.GetProperty(countPropertyName);
-            return source.AverageWithCount(averageProperty, countProperty);
+            return source.AverageWithCount(averageProperty, countProperty, resultType);
         }
-        public static object AverageWithCount(this IQueryable source, PropertyInfo averageProperty, PropertyInfo countProperty)
+        public static object AverageWithCount(this IQueryable source, PropertyInfo averageProperty, PropertyInfo countProperty, Type resultType)
         {
             if (source == null) throw new ArgumentNullException(nameof(source));
             if (averageProperty == null) throw new ArgumentNullException(nameof(averageProperty));
             if (countProperty == null) throw new ArgumentNullException(nameof(countProperty));
             //获取sum
             var sum = source.AverageSum(averageProperty, countProperty);
-            var count = source.Sum(countProperty);
-            var constantSum = Expression.Constant(sum);
-            var constantCount = Expression.Constant(count);
-            var unaryExpression = Expression.Convert(constantCount, sum.GetType());
-            var binaryExpression = Expression.Divide(constantSum, unaryExpression);
+            var count = source.SumByProperty(countProperty);
+            return AverageConstant(sum, count,resultType);
+            //var constantSum = Expression.Constant(sum);
+            //var constantCount = Expression.Constant(count);
+            //var unaryExpression = Expression.Convert(constantCount, sum.GetType());
+            //var binaryExpression = Expression.Divide(constantSum, unaryExpression);
+            //var invoke = Expression.Lambda(binaryExpression).Compile().DynamicInvoke();
+            //return invoke;
+        }
+
+        public static object AverageConstant(object sum, object count,Type resultType)
+        {
+
+            Expression constantSum = Expression.Constant(sum);
+            //如果计算类型和返回类型不一致先转成一致
+            if(sum.GetType()!=resultType)
+                constantSum = Expression.Convert(constantSum, resultType);
+            Expression constantCount = Expression.Constant(count);
+            //如果计算类型和返回类型不一致先转成一致
+            if (count.GetType() != resultType)
+                constantCount = Expression.Convert(constantCount, resultType);
+            var binaryExpression = Expression.Divide(constantSum, constantCount);
             var invoke = Expression.Lambda(binaryExpression).Compile().DynamicInvoke();
             return invoke;
         }
@@ -284,29 +318,25 @@ public static object AverageWithCount(this IQueryable source, PropertyInfo avera
         /// <param name="source">数据源</param>
         /// <param name="averagePropertyName">聚合函数average属性名</param>
         /// <param name="sumPropertyName">聚合函数sum属性名</param>
+        /// <param name="resultType">平均值返回结果:int/int=double</param>
         [ExcludeFromCodeCoverage]
-        public static object AverageWithSum(this IQueryable source, string averagePropertyName, string sumPropertyName)
+        public static object AverageWithSum(this IQueryable source, string averagePropertyName, string sumPropertyName, Type resultType)
         {
             if (source == null) throw new ArgumentNullException(nameof(source));
             if (averagePropertyName == null) throw new ArgumentNullException(nameof(averagePropertyName));
             if (sumPropertyName == null) throw new ArgumentNullException(nameof(sumPropertyName));
             var averageProperty = source.ElementType.GetProperty(averagePropertyName);
             var sumProperty = source.ElementType.GetProperty(sumPropertyName);
-            return source.AverageWithSum(averageProperty, sumProperty);
+            return source.AverageWithSum(averageProperty, sumProperty, resultType);
         }
-        public static object AverageWithSum(this IQueryable source, PropertyInfo averageProperty, PropertyInfo sumProperty)
+        public static object AverageWithSum(this IQueryable source, PropertyInfo averageProperty, PropertyInfo sumProperty, Type resultType)
         {
             if (source == null) throw new ArgumentNullException(nameof(source));
             if (averageProperty == null) throw new ArgumentNullException(nameof(averageProperty));
             if (sumProperty == null) throw new ArgumentNullException(nameof(sumProperty));
             var count = source.AverageCount(averageProperty, sumProperty);
-            var sum = source.Sum(sumProperty);
-            var constantCount = Expression.Constant(count);
-            var constantSum = Expression.Constant(sum);
-            var unaryExpression = Expression.Convert(constantCount, constantSum.GetType());
-            var binaryExpression = Expression.Divide(constantSum, unaryExpression);
-            var invoke = Expression.Lambda(binaryExpression).Compile().DynamicInvoke();
-            return invoke;
+            var sum = source.SumByProperty(sumProperty);
+            return AverageConstant(sum, count, resultType);
         }
         /// <summary>
         /// 获取平均数和 [{avg1,count1},{avg2,count2}....]=>sum(avg1...n*count1...n)/sum(count1...n)

src/ShardingCore/Sharding/Enumerators/StreamMergeAsync/MultiAggregateOrderStreamMergeAsyncEnumerator.cs

@@ -182,7 +182,7 @@ private void MergeValue(List<T> aggregateValues)
                             object aggregateValue = null;
                             if (aggregate is SelectCountProperty  || aggregate is SelectSumProperty)
                             {
-                                aggregateValue = aggregateValues.AsQueryable().Sum(aggregate.Property);
+                                aggregateValue = aggregateValues.AsQueryable().SumByProperty(aggregate.Property);
                             }
                             else if (aggregate is SelectMaxProperty)
                             {
@@ -196,11 +196,11 @@ private void MergeValue(List<T> aggregateValues)
                             {
                                 if (selectAverageProperty.CountProperty!=null)
                                 {
-                                    aggregateValue = aggregateValues.AsQueryable().AverageWithCount(selectAverageProperty.Property, selectAverageProperty.CountProperty);
+                                    aggregateValue = aggregateValues.AsQueryable().AverageWithCount(selectAverageProperty.Property, selectAverageProperty.CountProperty,selectAverageProperty.Property.PropertyType);
                                 }
                                 else if (selectAverageProperty.SumProperty != null)
                                 {
-                                    aggregateValue = aggregateValues.AsQueryable().AverageWithSum(selectAverageProperty.Property, selectAverageProperty.SumProperty);
+                                    aggregateValue = aggregateValues.AsQueryable().AverageWithSum(selectAverageProperty.Property, selectAverageProperty.SumProperty, selectAverageProperty.Property.PropertyType);
                                 }
                                 else
                                 {