mysql - SQL 将两个表中的值相乘并打印语句？

Question

从两个不同的表计算sum(频率*权重)后，如果总和大于某个数字，我试图打印出一条语句(如下)，但我不断收到错误这表示 total 不是有效列。

如有任何帮助，我们将不胜感激。提前致谢

DECLARE @total INT

SELECT SUM(frequency * weight) AS total
  FROM WF, WW
 WHERE WF.word = WW.word

IF total > 30
BEGIN
  print 'Alert! Bullying post'
END
ELSE
BEGIN
  print'Normal Post'
END

Answer 1

declare @Total as Int;

select @Total = Sum( WF.Frequency * WW.Weight )
  from WF inner join
    WW on WW.Word = WF.Word;

print case when @Total > 30 then 'Alert! Bullying post!' else 'Normal post.' end;