Question

我的总和不能为零。所以我用一个子查询来实现它。问题在于子查询不是很快。您将如何提高效率？

select * from (
      SELECT a,
             b, 
             c, 
             sum(d) as  ftd 
            FROM items f 
            WHERE f.category = 'ANY' AND 
                  f.version = 'V2018' AND 
                  f.month = '01' AND 
                  f.year = '2017'
            Group by  f.a, 
                     f.b, 
                     f.c 
            ORDER BY f.a, 
                     f.b, 
                     f.c
    )where ftd!=0;

Answer 1

使用HAVING

  SELECT a,
         b, 
         c, 
         sum(d) as  ftd 
        FROM items f 
        WHERE f.category = 'ANY' AND 
              f.version = 'V2018' AND 
              f.month = '01' AND 
              f.year = '2017'
        Group by  f.a, 
                 f.b, 
                 f.c 
       HAVING sum(d) != 0

Answer 2

您可以使用HAVING子句解决此问题：

SELECT a,
b, 
c, 
sum(d) as  ftd 
FROM items f 
WHERE f.category = 'ANY' AND 
f.version = 'V2018' AND 
f.month = '01' AND 
f.year = '2017'
Group by  f.a, 
f.b, 
f.c 
HAVING SUM(f.d)<>0
ORDER BY f.a, 
f.b, 
f.c

我该如何删除结果，使我得到零总和，而不使用子查询？

2 个答案: