Question

我正在将MS Access数据库移至MySQL，但是我遇到了一些查询问题。

我已经完成了将查询转移到80％的工作，但是这一特殊问题给我带来了麻烦。

TRANSFORM Nz(Max(IIf([charge_description_code] In ('AHS','AHW','AHL','RES','SAT'),"Y","N")), "N") AS Data
SELECT shipment_details.tracking_number, shipment_details.invoice_number
FROM shipment_details
WHERE tracking_number is not null
and charge_category_detail_code not in ('RADJ')
GROUP BY shipment_details.tracking_number, shipment_details.invoice_number
PIVOT shipment_details.charge_description_code In (SAT,AHW,AHS,AHL,RES);

我希望结果显示如下：

tracking_number invoice_number  SAT AHW AHS AHL RES
1Z2XXXXXXXXX625816  1329102975  N   N   N   N   N
1Z3YYYYYYYYY610514  1329109647  N   N   Y   N   N
1Z3ZZZZZZZZZ142605  1329109647  N   N   N   Y   Y

Answer 1

请考虑条件聚合，该条件聚合仍将在MS Access中起作用（将IF替换为下面的IIF）。通常，Access的交叉表查询不仅仅针对少数几个，而且还针对少数几个数据透视表。另外，您的NZ是多余的，因为NULL根据条件逻辑解析为N。

SELECT s.tracking_number, 
       s.invoice_number,
       MAX(IF(s.[charge_description_code] = 'SAT', 'Y', 'N')) AS 'SAT',
       MAX(IF(s.[charge_description_code] = 'AHW', 'Y', 'N')) AS 'AHW',
       MAX(IF(s.[charge_description_code] = 'AHL', 'Y', 'N')) AS 'AHL',
       MAX(IF(s.[charge_description_code] = 'AHS', 'Y', 'N')) AS 'AHS',
       MAX(IF(s.[charge_description_code] = 'RES', 'Y', 'N')) AS 'SAT'

FROM shipment_details s
WHERE s.tracking_number IS NOT NULL
  AND s.charge_category_detail_code NOT IN ('RADJ')
  AND s.charge_description_code IN ('AHS','AHW','AHL','RES','SAT')

GROUP BY s.tracking_number, 
         s.invoice_number

Answer 2

我认为transform返回未设置任何值的行。在这种情况下，适当的转换更像这样：

SELECT s.tracking_number, s.invoice_number,
       MAX(CASE WHEN s.charge_description_code = 'SAT' THEN 'Y' ELSE 'N' END) AS SAT,
       MAX(CASE WHEN s.charge_description_code = 'AHW' THEN 'Y' ELSE 'N' END) AS AHW,
       MAX(CASE WHEN s.charge_description_code = 'AHL' THEN 'Y' ELSE 'N' END) AS AHL,
       MAX(CASE WHEN s.charge_description_code = 'AHS' THEN 'Y' ELSE 'N' END) AS AHS,
       MAX(CASE WHEN s.charge_description_code = 'RES' THEN 'Y' ELSE 'N' END) AS RES
FROM shipment_details s
WHERE s.tracking_number IS NOT NULL AND
      s.charge_category_detail_code NOT IN ('RADJ')
GROUP BY s.tracking_number, s.invoice_number;

MS Access转换查询到MySQL查询

2 个答案: