Update mongodb

Src/Asp.NetCore2/SqlSugar.MongoDbCore/ExpToSql/VisitorItems/AnyMethods/ProcessAnyExpression.cs

@@ -80,7 +80,7 @@ namespace SqlSugar.MongoDb
                 throw new Exception("Expressions are not supported." + lambda.ToString());
             }
 
-            // 生成 $expr 查询，增加 $ifNull 逻辑
+            // 生成 $expr 查询，兼容 null 和空集合
             var expr = new BsonDocument
             {
                 {
@@ -100,6 +100,14 @@ namespace SqlSugar.MongoDb
                                                     { "input", $"${collectionField2}" },
                                                     { "as", paramName },
                                                     { "cond", new BsonDocument
+                                                        {
+                                                            { "$and", new BsonArray
+                                                                {
+                                                                    new BsonDocument
+                                                                    {
+                                                                        { "$isArray", $"$${paramName}.{nestedCollectionField}" }
+                                                                    },
+                                                                    new BsonDocument
                                                                     {
                                                                         { "$gt", new BsonArray
                                                                             {
@@ -125,6 +133,9 @@ namespace SqlSugar.MongoDb
                                                         }
                                                     }
                                                 }
+                                            }
+                                        }
+                                    }
                                 },
                                 0
                             }