code: public SelectBuilder from(Class<?> entityClass) {
      if (rootTable == null) {
        rootTable = new TableInfo(entityClass, dialect);
        currentTable = rootTable;
      } else {
        join(entityClass);
      }
      tables.add(currentTable);
  
      return this;
    }
docs: Retrieves the columns from the given entity and inner joins it to the previous entity given to the builder.
  
  entityClass becomes the current entity.