diff --git a/src/pgsql.hpp b/src/pgsql.hpp
index 282045601..fa8fb61bd 100644
--- a/src/pgsql.hpp
+++ b/src/pgsql.hpp
@@ -64,7 +64,7 @@ class pg_result_t
      */
     std::string get_value_as_string(int row, int col) const noexcept
     {
-        return std::string(get_value(row, col), get_length(row, col));
+        return std::string(get_value(row, col), (std::size_t)get_length(row, col));
     }
 
     /**