mysql - 想要从常规值中将平均值插入到仅 2008 年的平均值表中

Question

想将常规值表中的平均值仅作为平均值插入到 2008 年的平均值表中，但代码有错误，我是如何克服的。没有“where year(DATE_FORMAT(date, '%y-%m-%d'))= 2008”查询效果很好

INSERT IGNORE INTO `clima_data`.`avg_month_val1`  ( `year` , `month` ,  `evep` , `sunshine_hrs` , `rainfall` , `max_temp` , `min_temp` ) 

SELECT year(str_to_date(date, '%Y-%m-%d'))as year,
       month(str_to_date(date, '%Y-%m-%d'))as month,
       round(avg(evep),2) ,      
       round(Avg(sunshine_hrs),2),
       round(sum(rainfall),2),
       round(AVG(max_temp),2) ,
       round(avg(min_temp),2) 
 FROM reg_data3
 GROUP BY year(str_to_date(date, '%Y-%m-%d')),
          month(str_to_date(date, '%Y-%m-%d')) 
 WHERE year(DATE_FORMAT(date, '%y-%m-%d'))= 2008 
 ORDER BY 1 Desc

Answer 1

简单地做

 
  WHERE year(date)= 2008
  GROUP BY year(date), month(date)
 

代替

 GROUP BY year(str_to_date(date, '%Y-%m-%d')),
          month(str_to_date(date, '%Y-%m-%d'))
 WHERE year(DATE_FORMAT(date, '%y-%m-%d'))= 2008

Year 函数会自动为您进行转换，您也会从速度中受益。