使用 bicond 获取 ID？

Question

我有这个叫做joinTbl的表的sn-p：

PRODUCT_ID  PRODUCT_NAME    ORDER_ID     PRODUCT_ID      CUSTOMER_ID     SALESPERSON_ID      UNIT_PRICE 
   11          CAKE           10946          11               83              1                  31
   11          CAKE           10949          11               10              2                  31
   11          CAKE           11020          11               56              2                  31
   14          CHICKEN        11076          14               9               4                  23.25
   11          CAKE           11077          11               65              1                  31
   14          CHICKEN        11077          14               65              1                  23.25

在 Pig Apache 中，如果订单同时包含蛋糕和鸡肉，我会尝试获取 ORDER_ID。预期结果是

11077

但是我在尝试做一个 bicond 来获得这个ORDER_ID 时遇到了问题。这是我使用的语法：

cakeChicken = FOREACH joinedTbl GENERATE ((PRODUCT_NAME == 'CAKE' AND PRODUCT_NAME == 'CHICKEN') ? ORDER_ID : 0) AS order_both;

从这里返回的只是 0 这是 else 语句。

我做错了什么？

Answer 1

您的 bincond 工作正常 - 因为它位于 FOREACH 内，它会单独检查每一行数据。因此，每一行将只有一个PRODUCT_NAME 的值，因此它不能同时是'CAKE' 和'CHICKEN'。

根据您想要做的，我将 use GROUP BY 分组到 ORDER_ID 然后 filter 和 PRODUCT_NAME 袋子只包含 'CAKE' 和 'CHICKEN' 使用 nested foreach。最后，将数据过滤到“非空”包中。像这样的：

groupedData = GROUP  joinTbl BY ORDER_ID;

/* Structure:
---------------------------------------------------------------------------------------------------------------------------------
| groupedData | group | joinTbl: bag({PRODUCT_ID, PRODUCT_NAME, ORDER_ID, PRODUCT_ID, CUSTOMER_ID, SALESPERSON_ID, UNIT_PRICE}) |
---------------------------------------------------------------------------------------------------------------------------------
|             | 10946 | {(11, CAKE, 10946, 11, 83, 1, 31)}                                                                      |
|             | 11077 | {(11, CAKE, 11077, 11, 65, 1, 31), (14, CHICKEN,  11077, 14, 65, 1, 23.25)}                             |
---------------------------------------------------------------------------------------------------------------------------------
*/

cakeChickenIds = FOREACH groupedData {
    cakes = FILTER joinTbl BY PRODUCT_NAME == 'CAKE';
    chickens = FILTER joinTbl BY PRODUCT_NAME == 'CHICKEN';
    GENERATE group AS ORDER_ID,
    cakes,
    chickens;
}

/* Structure:
------------------------------------------------------------------------------------------
| cakeChickenIds | ORDER_ID | cakes: bag({PRODUCT_NAME}) | chickens: bag({PRODUCT_NAME}) |
------------------------------------------------------------------------------------------
|                | 10946    | {(CAKE)}                   | {()}                          |
|                | 11077    | {(CAKE)}                   | {(CHICKEN)}                   |
------------------------------------------------------------------------------------------
*/

-- Both cakes and chickens bags will not be empty if ordered both
cakeChickenOrders = FILTER cakeChickenIds BY NOT IsEmpty(cakes) AND NOT IsEmpty(chickens);