Mysql不通过触发器更新同表不同列的avg函数

Question

我正在尝试更新特定列 column_2取 column_1 行的平均值值其中 column_3 =值

但它给出了一个错误

我的代码

Error: Can't update table 'moving_average' in stored function/trigger because it is already used by statement which invoked this stored function/trigger.

delimiter $$

Create TRIGGER takeaverage AFTER insert ON moving_table 
FOR EACH ROW  
BEGIN        
update moving_table b, (select avg(price) avg_ from moving_table ) v
set
  b.moving_avg = v.avg_price;


END;

Answer 1

根据documentaion，您不能这样做:

A stored function or trigger cannot modify a table that is already being used (for reading or writing) by the statement that invoked the function or trigger.

我宁愿编写一个 BEFORE INSERT 触发器，并使用现有行的平均值和新的 price 更新 :New.movi​​ng_avg。