MySQL的计数语句错误 - 操作数应包含1列（S）

Question

我试图做多计数大家正在接受第一子选择（列表1）我得到的，上面写着“操作数应包含1列（或多个）错误“我猜它与AND有关，但我不确定我会如何解决这个问题。

Select Count(list0.ustatus) AS finished_count 
     , (Select list1.ustatus, Count(*) 
       From listofupdates list1 
      Where list1.ustarted != '0000-00-00 00:00:00' 
       AND list1.ustatus != 1 
      ) AS start_count 
     , (Select Count(list2.udifficulty) 
       From listofupdates list2 
      Where list2.udifficulty = 2 
      ) AS recheck_count 
     , (Select Count(list3.udifficulty) 
       From listofupdates list3 
       Where list3.udifficulty = 4 
      ) AS question_count 
    From listofupdates as list0 
    Where list0.ustatus = 1 

Answer 1

我完全@Chad桦木

aggree以下查询应该工作。

Select Count(list0.ustatus) AS finished_count 
     , (Select Count(*) 
       From listofupdates list1 
      Where list1.ustarted != '0000-00-00 00:00:00' 
       AND list1.ustatus != 1 
      ) AS start_count 
     , (Select Count(list2.udifficulty) 
       From listofupdates list2 
      Where list2.udifficulty = 2 
      ) AS recheck_count 
     , (Select Count(list3.udifficulty) 
       From listofupdates list3 
       Where list3.udifficulty = 4 
      ) AS question_count 
    From listofupdates as list0 
    Where list0.ustatus = 1 

Answer 2

问题的最有可能在所述线路与

FROM listofupdates LISTX

（其中X为0，1，2，3）

这似乎是在这些情况下，只有list0，list1，list2，list3就足够了。

Answer 3

在第一个子选择中，您试图选择2列。您只需要选择一个，除非您正在对结果进行比较，否则无法重新选择多个列。

请参阅MySQL Docs - Subquery Errors。