sql - ORACLE SQL 中的 MAX()

Question

我有一个表，其中存储了已完成维护任务的记录列表以及完成的日期和时间。我正在尝试执行子查询以提取具有最新日期的每个任务的记录。我的 SQL 语句是:

    SELECT "ENGINEERING_COMPLIANCE"."EO" AS "EO",
       "ENGINEERING_COMPLIANCE"."AC" AS "AC",
       "ENGINEERING_COMPLIANCE"."PN" AS "PN",
       "ENGINEERING_COMPLIANCE"."PN_SN" AS "PN_SN",
       "ENGINEERING_COMPLIANCE"."HOURS_RESET" AS "HOURS_RESET",
       "ENGINEERING_COMPLIANCE"."MINUTES_RESET" AS "MINUTES_RESET",
       "ENGINEERING_COMPLIANCE"."CYCLES_RESET" AS "CYCLES_RESET",
       "ENGINEERING_COMPLIANCE"."RESET_DATE" AS "RESET_DATE",
       "ENGINEERING_COMPLIANCE"."RESET_HOUR" AS "RESET_HOUR",
       "ENGINEERING_COMPLIANCE"."RESET_MINUTE" AS "RESET_MINUTE",
       MAX ( "ENGINEERING_COMPLIANCE"."RESET_DATE" ) AS "LAST_COMP_DATE"
  FROM ENGINEERING_COMPLIANCE
GROUP BY ( "ENGINEERING_COMPLIANCE"."EO" ) ,
       ( "ENGINEERING_COMPLIANCE"."AC" ) ,
       ( "ENGINEERING_COMPLIANCE"."PN" ) ,
       ( "ENGINEERING_COMPLIANCE"."PN_SN" )

但是我不断收到以下错误:“ORA-00979:不是 GROUP BY 表达式”

当我删除“GROUP BY”时，我得到:
“ORA-00937:不是单组组函数”

1 - 这到底是什么意思
2 - 声明有什么问题？

Answer 1

我根本不了解 MySQL，但是，在 Oracle 中，您需要按选择列表中列出的所有非聚合功能列进行分组。

这样的事情应该工作:

 SELECT "engineering_compliance"."eo"               AS "EO", 
       "engineering_compliance"."ac"               AS "AC", 
       "engineering_compliance"."pn"               AS "PN", 
       "engineering_compliance"."pn_sn"            AS "PN_SN", 
       "engineering_compliance"."hours_reset"      AS "HOURS_RESET", 
       "engineering_compliance"."minutes_reset"    AS "MINUTES_RESET", 
       "engineering_compliance"."cycles_reset"     AS "CYCLES_RESET", 
       "engineering_compliance"."reset_date"       AS "RESET_DATE", 
       "engineering_compliance"."reset_hour"       AS "RESET_HOUR", 
       "engineering_compliance"."reset_minute"     AS "RESET_MINUTE", 
       Max ("engineering_compliance"."reset_date") AS "LAST_COMP_DATE" 
FROM   engineering_compliance 
GROUP  BY "engineering_compliance"."eo", 
          "engineering_compliance"."ac", 
          "engineering_compliance"."pn", 
          "engineering_compliance"."pn_sn", 
          "engineering_compliance"."hours_reset", 
          "engineering_compliance"."minutes_reset", 
          "engineering_compliance"."cycles_reset", 
          "engineering_compliance"."reset_date", 
          "engineering_compliance"."reset_hour", 
          "engineering_compliance"."reset_minute";