int is long, select column can be function, some fixes..

just to get it work.. needs improvement

usql.h

@@ -10,7 +10,7 @@ namespace usql {
 class USql {
 
 public:
-    USql() {};
+    USql();
 
     std::unique_ptr<Table> execute(const std::string &command);
 
@@ -24,6 +24,7 @@ private:
     std::unique_ptr<Table> execute_delete(DeleteFromTableNode &node);
     std::unique_ptr<Table> execute_update(UpdateTableNode &node);
     std::unique_ptr<Table> execute_load(LoadIntoTableNode &node);
+    std::unique_ptr<Table> execute_save(SaveTableNode &node);
 
 
 private:
@@ -40,7 +41,7 @@ private:
     std::unique_ptr<ValueNode> evalArithmeticOperator(ColumnType outType, ArithmeticalOperatorNode &node, Table *table, Row &row) const;
 
 
-    std::unique_ptr<Table> create_stmt_result_table(int code, std::string text);
+    std::unique_ptr<Table> create_stmt_result_table(long code, std::string text);
     Table *find_table(const std::string name);