错误979：不是GROUP BY表达式

Question

尝试返回最后联系日期时出错

SELECT CDC.pat_id, MAX(SOC.contact_date), 
FROM hb61.cdcsaar_patients CDC
JOIN clarity.social_hx SOC ON CDC.pat_id=SOC.pat_id
LEFT OUTER JOIN clarity.smoking_cess_hx CESS ON CDC.pat_id=CESS.pat_id
LEFT OUTER JOIN clarity.social_hx_alc_use ALC on CDC.pat_id=ALC.pat_id
GROUP BY SOC.contact_date
;

Answer 1

您需要将所选列（在本例中为 CDC.pat_id ）放在 GROUP BY 子句中，而不是将您应用于聚合功能

SELECT
  CDC.pat_id,
  MAX(SOC.contact_date)
FROM
  hb61.cdcsaar_patients CDC
  JOIN clarity.social_hx SOC ON CDC.pat_id = SOC.pat_id
  LEFT OUTER JOIN clarity.smoking_cess_hx CESS ON CDC.pat_id = CESS.pat_id
  LEFT OUTER JOIN clarity.social_hx_alc_use ALC on CDC.pat_id = ALC.pat_id
GROUP BY
  CDC.pat_id;

Answer 2

您需要将任何不的列应用聚合函数放入GROUP BY子句（在本例中为CDC.pat_id，而不是SOC.contact_date）。