code: public SQLInsertClause insertOnDuplicateKeyUpdate(RelationalPath<?> entity, Expression<?> clause) {
          SQLInsertClause insert = insert(entity);
          insert.addFlag(Position.END, ExpressionUtils.template(String.class, " on duplicate key update {0}", clause));
          return insert;
      }
docs: Create a INSERT ... ON DUPLICATE KEY UPDATE clause
  
  @param entity table to insert to
  @param clause clause
  @return insert clause