Question

我正在运行查询并收到以下PHP错误消息：Warning: mysqli::query(): (21000/1242): Subquery returns more than 1 row

当我将这些查询放入phpMyAdmin时，我收到此消息：#2014 - Commands out of sync; you can't run this command now

PHP版本5.5.18， MySql版本5.6.21

错误查询

select *, 
  (select stime 
    from racetype_standards 
    where eventID = 8 and stypeID=st.id and gender = 2 and division = 1) 
    as standscore, 
  (select floor(stime / 60) 
    from racetype_standards 
    where eventID = 8 and stypeID=st.id and gender = 2 and division = 1) 
    as standminutes, 
  (select (stime % 60) 
    from racetype_standards 
    where eventID = 8 and stypeID=st.id and gender = 2 and division = 1) 
    as standseconds, 
  (select substring_index(stime, '.', -1)
    from racetype_standards 
    where eventID = 8 and stypeID=st.id and gender = 2 and division = 1) 
    as standhunds, 
  (select ecomment 
    from racetype_standards 
    where eventID = 8 and stypeID=st.id and gender = 2 and division = 1) 
    as ecomm 
  from standards_type st 
  where active = 1 
  order by displayOrder

好查询

select *, 
  (select stime 
    from racetype_standards 
    where eventID = 7 and stypeID=st.id and gender = 2 and division = 1) 
    as standscore, 
  (select floor(stime / 60) 
    from racetype_standards 
    where eventID = 7 and stypeID=st.id and gender = 2 and division = 1) 
    as standminutes, 
  (select (stime % 60)
    from racetype_standards 
    where eventID = 7 and stypeID=st.id and gender = 2 and division = 1) 
    as standseconds, 
  (select substring_index(stime, '.', -1) 
    from racetype_standards
    where eventID = 7 and stypeID=st.id and gender = 2 and division = 1) 
    as standhunds, 
  (select ecomment 
    from racetype_standards 
    where eventID = 7 and stypeID=st.id and gender = 2 and division = 1) 
    as ecomm 
  from standards_type st 
  where active = 1 
  order by displayOrder

Answer 1

其中每一项：

(select stime 
    from racetype_standards 
    where eventID = 8 and stypeID=st.id and gender = 2 and division = 1)

必须解析为一行 - 对于任何给定的st.id，不能有两行符合这些条件。如果两行，则需要在每个内部查询中按st.id进行分组，并以某种方式汇总stime（例如，选择max(stime)）和每个其他子查询都相同。

或者，如果您希望能够为每个racetype_standards行返回多行，那么构建它可能会有很大不同 - 可能通过执行连接。目前这是一个非常难以维护的查询，因为它做了相同的事情5次[基本上] - 如果你修改它只需要那么很多子查询一次（例如，通过使其成为连接）。在我更常用的SQL风格中，我会执行一次子查询，然后引用新创建的列来执行所有其他位，例如（不确定在mysql中是否可行）;另外，我只会把时间拉一次，然后将其留给目标文本构建器（即PHP）来构建分钟/秒/诸如此类的东西 - 更少的代码来维护。

但是，无论哪种方式，我都会尝试将其作为连接 - 似乎您最终需要所有各种eventID？只需将桌子拉下来，然后从那里处理它。

警告：mysqli :: query（）:( 21000/1242）：子查询返回多行

1 个答案: