新手问题,帮帮忙

sbSql = sbSql.Append(" select")
sbSql = sbSql.Append(" t1.ShopID ShopID")
sbSql = sbSql.Append(" ,t1.Name GoodsName")
sbSql = sbSql.Append(" ,t1.Kbn Kbn") '原表名
sbSql = sbSql.Append(" ,t1.Price Price")
sbSql = sbSql.Append(" ,t1.SalePrice SalePrice")
sbSql = sbSql.Append(" ,t1.BuyPrice BuyPrice")
sbSql = sbSql.Append(" ,t1.MakerID MakerID")
sbSql = sbSql.Append(" ,t1.SaleDay SaleDay")
sbSql = sbSql.Append(" ,t1.SaleFlg SaleFlg")
sbSql = sbSql.Append(" ,t2.Name MakerName")
sbSql = sbSql.Append(" ,t3.CodeValue KbnName")
sbSql = sbSql.Append(" ,t4.CodeValue SaleFlgName")
sbSql = sbSql.Append(" from shop t1, Maker t2, Code t3, Code t4")
sbSql = sbSql.Append(" where")
sbSql = sbSql.Append(" t1.MakerID = t2.MakerID")
sbSql = sbSql.Append(" and t3.CodeKbn = '03'")
sbSql = sbSql.Append(" and t3.Code = t1.Kbn")
sbSql = sbSql.Append(" and t4.CodeKbn = '04'")
sbSql = sbSql.Append(" and t4.Code = t1.SaleFlg")
sbSql = sbSql.Append(" and t1.Delflg = '0'")
sbSql = sbSql.Append(" and t1.Kbn like ?t1.Kbn")
sbSql = sbSql.Append(" and t1.Name like ?t1.Name")
sbSql = sbSql.Append(" and t1.SaleDay >= ?t1.SaleDayS")
sbSql = sbSql.Append(" and t1.SaleDay <= ?t1.SaleDayE")
sbSql = sbSql.Append(" and t2.Name like ?t2.Name")
sbSql = sbSql.Append(" order by GoodsID")
帮忙看看这些代码,里面的 sbSql = sbSql.Append(" t1.ShopID ShopID")是什么意思啊?由其不明白里面的 "t1.ShopID"为什么要这样写?高手帮帮忙,多谢了!