fix load data handle empty filed bug

src/sql/engine/cmd/ob_load_data_impl.cpp

@@ -1231,7 +1231,7 @@ int ObLoadDataImpl::handle_one_line(ObExecContext& ctx, ObPhysicalPlanCtx& plan_
   return ret;
 }
 
-const char* ObCSVParser::ZERO_STRING = "0";
+const char* ObCSVParser::ZERO_STRING = "\xFF\xFF";
 
 int ObCSVParser::init(
     int64_t file_column_nums, const ObCSVFormats& formats, const common::ObBitSet<>& string_type_column)
@@ -1355,7 +1355,7 @@ void ObCSVParser::deal_with_empty_field(ObString& field_str, int64_t index)
 {
   if (formats_.null_column_fill_zero_string_ && !string_type_column_.has_member(index)) {
     // a non-string value will be set to "0", "0" will be cast to zero value of target types
-    field_str.assign_ptr(ZERO_STRING, 1);
+    field_str.assign_ptr(ZERO_STRING, 2);
   } else {
     // a string value will be set to ''
     field_str.reset();
@@ -2831,6 +2831,8 @@ int ObLoadDataSPImpl::exec_insert(ObInsertTask& task, ObInsertResult& result)
         }
         if (ObLoadDataUtils::is_null_field(single_row_values[c])) {
           OZ(sql_str.append(ObString(ObLoadDataUtils::NULL_STRING)));
+        } else if (ObLoadDataUtils::is_zero_field(single_row_values[c])) {
+          OZ(sql_str.append("0"));
         } else {
           if (is_string_column) {
             OZ(sql_str.append("'", 1));

src/sql/engine/cmd/ob_load_data_utils.h

@@ -147,6 +147,15 @@ public:
     return ret_bool;
   }
 
+  static inline bool is_zero_field(const common::ObString& field_str)
+  {
+    int ret_bool = false;
+    if (field_str.length() == 2 && field_str.ptr()[0] == '\xff' && field_str.ptr()[1] == '\xff') {
+      ret_bool = true;
+    }
+    return ret_bool;
+  }
+
   static common::ObString escape_quotation(const common::ObString& value, common::ObDataBuffer& data_buf);
   static int init_empty_string_array(common::ObIArray<common::ObString>& new_array, int64_t array_size);