減算は、私のクエリ後SUM

Question

で正常に動作しません：

SELECT SUM(t*q) as first, 
SUM(s*q) AS second, 
SUM(t*q)-SUM(s*q) AS firstminussecond 
FROM my_table 

結果は次のとおりです。

first = 9010.56 
second = 8664 
firstminussecond = 346.5599999999995 (this should be 346.56!) 

firstminussecondが正しくないのはなぜ？これを解決するには？あなたはROUND機能を使用する必要が

SELECT SUM(t*q) as first, 
SUM(s*q) AS second, 
FORMAT(SUM(t*q)-SUM(s*q),2) AS firstminussecond 
FROM my_table 

Answer 1

私は私の意見では、正しい解決策を見つけ、私はINT(11)にDECIMAL(10,2)とqに列tとsのデータ型を変更しました。今すぐfirstminussecondが正しいです。

Answer 2

は、

SELECT 
      ROUND(SUM(t*q),2) as first, 
      ROUND(SUM(s*q),2) AS second, 
      (
      ROUND(SUM(t*q),2)- 
      ROUND(SUM(s*q),2) 
      ) AS firstminussecond 
    FROM my_table 

OR

SELECT 
      ROUND(SUM(t*q),2) as first, 
      ROUND(SUM(s*q),2) AS second, 
      ROUND(
        (ROUND(SUM(t*q),2)- 
        ROUND(SUM(s*q),2)) 
       ,2) AS firstminussecond 
    FROM my_table 

Answer 3

これを試してくださいあなたはこれで試すことができます。

SELECT SUM(t*q) AS first, 
SUM(s*q) AS second, 
ROUND(SUM(t*q)-SUM(s*q), 2) AS firstminussecond 
FROM my_table 

Answer 4

SELECT SUM(t*q) as first, 
SUM(s*q) AS second, 
cast(SUM(t*q)-SUM(s*q) as decimal(5,2)) AS firstminussecond 
FROM my_table 

Answer 5

：