Oracle分組查詢中包含子查詢列，發生ORA-00937：不是單分組函式的錯誤

 select sum(raw_ore) raw_ore
 ,(select sum(raw_ore0) from trv_daily where p_year=a.p_year ) lift_ore   
  from trv_refine a  where p_year=2024

儘管語句select sum(raw_ore0) from trv_daily where p_year=a.p_year ，只返回一個數值，系統提示“ORA-00937：不是單分組函式”

將子查詢外面新增max等統計函式，即可解決該問題。

 select sum(raw_ore) raw_ore
 ,max((select sum(raw_ore0) from trv_daily where p_year=a.p_year )) lift_ore   
  from trv_refine a  where p_year=2024

總結：在分組查詢中，只允許2類列，分組依據列（group by）和分組查詢列（sum、count）等。