如果你只想要最新的那一排 LastCompleted 每 EQUIPMENT 应用等级/行号：

SELECT
    SE.EquipmentSurfaceAssetBK AS "MRC",
    SE.EquipmentCodeBK AS "EQUIPMENT",
    SE.EquipmentDescription AS "DESCRIPTION",
    SE.EquipmentClassBK AS "CLASSCODE",
    SE.EquipmentCriticality AS "CRITICALITY",
    SE.EquipmentCostCode AS "COSTCODE",
    SE.EquipmentStatus AS "STATUS",
    PE.EqPMCodeBK AS "PM",
    PM.PMDescription AS "PMDESCRIPTION",
    PE.EqPMDueDate AS "NEXTDUE",
    PE.EqPMType AS "PMTYPE",
    PE.EqPMDeactivatedDate AS "DDATE",
    PE.EqPMAssignedBy AS "ASSIGNEDBY",
    PE.EqPMAssignedToResourceBK AS "ASSIGNEDTO",
    PE.EqPMFrequency AS "FREQUENCY",
    PE.EqPMFrequencyUOM AS "UOM",
    WO.WorkOrderEquipmentcodeBK AS "WOEQUIP",
    WO.WorkOrderCodeBK AS "WORKORDER",
    WO.WorkOrderPMCodeBK AS "WORKORDERPM",
    CASE
        WHEN WO.WorkOrderPMCodeBK = PE.EqPMCodeBK THEN 'YES' ELSE 'NO'
    END AS "CHECKS",
    WO.WorkOrderStatus AS "WOSTATUS",
    WO.WorkOrderCompletedDate AS "LastCompleted"
FROM IDW_PL_SURFACE.DIMSurfaceEquipment SE 
JOIN IDW_PL_SURFACE.DIMEquipmentPM PE
  ON SE.EquipmentCodeBK = PE.EqPMEquipmentCodeBK
JOIN IDW_PL_SURFACE.DIMSurfacePM PM
  ON PE.EqPMCodeBK = PM.PMCodeBK
JOIN IDW_PL_SURFACE.DIMWorkOrder WO
  ON SE.EquipmentCodeBK = WO.WorkOrderEquipmentcodeBK
WHERE 1=1
  AND STATUS IN ( 'I', 'IDLE')
  AND DDATE is Null
  AND PMTYPE IN (  'V', 'F')
  AND "CHECKS" IN ( 'YES')

QUALIFY RANK() OVER (PARTITION BY EQUIPMENT ORDER BY LastCompleted) = 1

“select”中的非聚合列与“groupby”中列出的列不匹配。您可以将select中的所有内容（lastcompleted除外）添加到group by，也可以从select中删除一组列：

select
  EQUIPMENT,
  MAX(LastCompleted) as CDATE
from
--your subquery here
where STATUS in ('I','IDLE')
  and DDATE is Null
  and PMTYPE in ('V','F')
  and "CHECKS" in ('YES')
group by
  EQUIPMENT