嵌套的if语句

Question

我不知道SQL也不知道嵌套语句。请根据我的条件和SQL在下面提供完整的SQL来复制并粘贴到我的Access查询中。 非常感谢你，Nathaniel

标准：

1. if [POsoI].[PO_number]is like "*H", THEN [o].[SERVICE ID] must be equal to "HEAT TREAT"

2. IF [POsoI].[PO_number] is like "*C", THEN [o].[SERVICE ID] must be equal to "COATING" or equal to "ZINC PLATING"

3. IF [POsoI].[PO_number] is like "*G", THEN [o].[SERVICE ID] must be equal to "GRINDING"

4. IF [POsoI].[.[PO_number] isnt like "*H" or like "*C" or like "*G", then [o].[SERVICE ID] must not be null and can not be equal to "HEAT TREAT" and can not be equal to "COATING" and can not be equal to"ZINC PLATING" and can not be equal to "GRINDING"

   SELECT DISTINCT o.SERVICE_ID FROM tbl_PO_service_order_input AS POsoI INNER JOIN SYSADM_OPERATION AS o ON (o.WORKORDER_LOT_ID = POsoI.WO_lot_ID) AND (POsoI.wo_Base_ID = o.WORKORDER_BASE_ID);

Answer 1

SELECT DISTINCT IIf(RIGHT(TBL_PO_SERVICE_ORDER_INPUT.PO_NUMBER,1)='H' And SYSADM_OPERATION.SERVICE_ID='HEAT TREAT',SYSADM_OPERATION.SERVICE_ID,IIf(RIGHT(TBL_PO_SERVICE_ORDER_INPUT.PO_NUMBER,1)='C' And SYSADM_OPERATION.SERVICE_ID='CLOTHING' Or SYSADM_OPERATION.SERVICE_ID='ZINC PLATING',SYSADM_OPERATION.SERVICE_ID,IIf(RIGHT(TBL_PO_SERVICE_ORDER_INPUT.PO_NUMBER,1)='G' And SYSADM_OPERATION.SERVICE_ID='GRINDING',SYSADM_OPERATION.SERVICE_ID,IIf(RIGHT(TBL_PO_SERVICE_ORDER_INPUT.PO_NUMBER,1)<>'G' Or RIGHT(TBL_PO_SERVICE_ORDER_INPUT.PO_NUMBER,1)<>'H' Or RIGHT(TBL_PO_SERVICE_ORDER_INPUT.PO_NUMBER,1)<>'C' And SYSADM_OPERATION.SERVICE_ID Is Not Null,SYSADM_OPERATION.SERVICE_ID,
IIf(SYSADM_OPERATION.SERVICE_ID<>'HEAT TREAT' And SYSADM_OPERATION.SERVICE_ID<>'COATING' And SYSADM_OPERATION.SERVICE_ID<>'ZINC PLATING' And SYSADM_OPERATION.SERVICE_ID<>'GRINDING',SYSADM_OPERATION.SERVICE_ID)))))
FROM SYSADM_OPERATION INNER JOIN TBL_PO_SERVICE_ORDER_INPUT ON ([TBL_PO_SERVICE_ORDER_INPUT].WO_LOT_ID=[SYSADM_OPERATION].WORKORDER_LOT_ID) AND ([TBL_PO_SERVICE_ORDER_INPUT].WO_BASE_ID=[SYSADM_OPERATION].WORKORDER_BASE_ID);