fix casing issue when sql table is case insensitive

src/SqlAsyncCollector.cs

@@ -315,6 +315,12 @@ private static void GenerateDataQueryForMerge(TableInformation table, IEnumerabl
                 else
                 {
                     // ToDo: add check for duplicate primary keys once we find a way to get primary keys.
+                    // JObjects ignore serializer settings (https://web.archive.org/web/20171005181503/http://json.codeplex.com/workitem/23853)
+                    // so we have to manually convert property names to lower case before inserting into the query in that case
+                    if (table.Comparer == StringComparer.OrdinalIgnoreCase)
+                    {
+                        (row as JObject).LowercasePropertyNames();
+                    }
                     rowsToUpsert.Add(row);
                 }
             }

src/Utils.cs

@@ -2,7 +2,10 @@
 // Licensed under the MIT License. See License.txt in the project root for license information.
 
 using System;
+using System.Linq;
 using Microsoft.Extensions.Configuration;
+using MoreLinq;
+using Newtonsoft.Json.Linq;
 
 namespace Microsoft.Azure.WebJobs.Extensions.Sql
 {
@@ -60,5 +63,35 @@ private static bool AsBool(this string str, bool defaultValue = false)
                     return defaultValue;
             }
         }
+
+        /// <summary>
+        /// Recursively converts the property names for a JObject to lowercase
+        /// </summary>
+        /// <param name="obj">The JToken to convert</param>
+        public static void LowercasePropertyNames(this JToken token)
+        {
+            if (token is JObject jObj)
+            {
+                token.LowercasePropertyNames();
+            }
+            else if (token is JArray jArray)
+            {
+                token.ForEach(x => x.LowercasePropertyNames());
+            }
+        }
+
+        /// <summary>
+        /// Recursively converts the property names for a JObject to lowercase
+        /// </summary>
+        /// <param name="obj">The JObject to convert</param>
+        public static void LowercasePropertyNames(this JObject obj)
+        {
+            foreach (JProperty property in obj.Properties().ToList())
+            {
+                property.Value.LowercasePropertyNames();
+                // properties are read-only, so we have to replace them
+                property.Replace(new JProperty(property.Name.ToLowerInvariant(), property.Value));
+            }
+        }
     }
 }