Accept default operator.

backend/src/Squidex.Infrastructure/Queries/Json/JsonFilterSurrogate.cs

@@ -46,9 +46,9 @@ namespace Squidex.Infrastructure.Queries.Json
                 return new LogicalFilter<IJsonValue>(LogicalFilterType.Or, Or);
             }
 
-            if (!string.IsNullOrWhiteSpace(Path) && Op != null)
+            if (!string.IsNullOrWhiteSpace(Path))
             {
-                return new CompareFilter<IJsonValue>(Path, Op.Value, Value ?? JsonValue.Null);
+                return new CompareFilter<IJsonValue>(Path, Op ?? CompareOperator.Equals, Value ?? JsonValue.Null);
             }
 
             throw new JsonException(Errors.InvalidJsonStructure());

backend/tests/Squidex.Infrastructure.Tests/Queries/QueryJsonTests.cs

@@ -38,6 +38,16 @@ namespace Squidex.Infrastructure.Queries
             Assert.Equal(expected, filter.ToString());
         }
 
+        [Fact]
+        public void Should_convert_comparison_without_operator()
+        {
+            var json = new { path = "property" };
+
+            var filter = SerializeAndDeserialize(json);
+
+            Assert.Equal("property == null", filter.ToString());
+        }
+
         [Fact]
         public void Should_convert_comparison_empty()
         {
@@ -141,14 +151,6 @@ namespace Squidex.Infrastructure.Queries
             Assert.ThrowsAny<JsonException>(() => SerializeAndDeserialize(json));
         }
 
-        [Fact]
-        public void Should_throw_exception_for_missing_operator()
-        {
-            var json = new { path = "property", value = 12 };
-
-            Assert.ThrowsAny<JsonException>(() => SerializeAndDeserialize(json));
-        }
-
         [Fact]
         public void Should_throw_exception_for_missing_value()
         {