Question

  SELECT month,Avg(rain_fall) FROM rain_fall WHERE 
  STR_TO_DATE( CONCAT('01','-',month,'-',year) , '%d-%b-%Y') 
  between
  STR_TO_DATE('01-Jan-1991','%d-%b-%Y') and
  STR_TO_DATE('01-Dec-1993','%d-%b-%Y')
  group by month
  order by MONTH(STR_TO_DATE( CONCAT('01','-',month,'-',year) , '%d-%b-%Y'))
  UNION
  SELECT month,Avg(data_value) FROM temprature_data WHERE 
  STR_TO_DATE( CONCAT('01','-',month,'-',year) , '%d-%b-%Y') 
  between
  STR_TO_DATE('01-Jan-1991','%d-%b-%Y') and
  STR_TO_DATE('01-Dec-1993','%d-%b-%Y')
  group by month
  order by MONTH(STR_TO_DATE( CONCAT('01','-',month,'-',year) , '%d-%b-%Y')) ;

以上是我的SQL查询。我希望得到一年中temprature_data table和rain_fall表中所有月份的平均值。

收到错误讯息：

＃1221 - UNION和ORDER BY的使用不正确

Answer 1

在每个void HandleManToggled(object sender, Xamarin.Forms.ToggledEventArgs e) { var s = sender as Switch; if (s.IsToggled) WomanGenderSwitch.IsToggled = false; else WomanGenderSwitch.IsToggled = false; } void HandleWomanToggled(object sender, Xamarin.Forms.ToggledEventArgs e) { var s = sender as Switch; if (s.IsToggled) ManGenderSwitch.IsToggled = false; else ManGenderSwitch.IsToggled = false; }查询和select上使用括号：

P.S。：UNION ALL是保留字。如果在这里，您使用的是列名，请尝试将其更改为其他内容，以免在以后的查询中发生冲突。 Check this list of reserved words in MySQL

month

如何从mysql中的两个表中获取结果

1 个答案: