仅对具有多行的组求和值

Question

我有这个查询：

SELECT extract(year from date1), extract(month from date1), spending    
FROM ( SELECT *, COUNT(*) OVER(PARTITION BY CONCAT(extract(year FROM date1), extract(month FROM date1))) N
       FROM table) as A    
WHERE N > 1    
GROUP BY date1    
ORDER BY date1 ASC;

结果如下：

只有当 equla year 和 month 超过一行时，我才需要对字段 spending 求和。期望的结果：

year    month   spending
----    -----   --------
2015     1        5424
2016     1      605886
2016     5      xxxxxx
....     ..     ......

Answer 1

好的，我找到了解决方案：HAVING :

SELECT extract(year from date1), extract(month from date1), spending    
FROM table  
GROUP BY extract(month from date1)), extract(year from date1), extract(month from date1)
HAVING count (CONCAT(extract(year from date1), extract(month from date1))) > 1
ORDER BY extract(year from date1), extract(month from date1) ASC;

以防对某人有帮助。

Answer 2

使用 date_trunc() 和一些简化可以更简单和更快：

SELECT date_trunc('month', date1)::date AS month
     , sum(spending)                    AS sum_spending
     , count(*)                         AS count_rows  -- optional addition
FROM   table
GROUP  BY 1
HAVING count(*) > 1
ORDER  BY 1;

只有 returns 超过一行的月份的支出总和。

如果您需要显示单独的年份和月份数字，您可以在子查询中使用上述查询，速度更快：

SELECT extract(year  FROM month)::int AS year
     , extract(month FROM month)::int AS month
     , sum_spending, count_rows
FROM (
   SELECT date_trunc('month', date1)::date AS month
        , sum(spending)                    AS sum_spending
        , count(*)                         AS count_rows  -- optional
   FROM   table
   GROUP  BY 1
   HAVING count(*) > 1
   ORDER  BY 1
   ) sub;

或者像在您的解决方案中一样直接提取数字，但只需在 HAVING 子句中使用更快的 count(*)：

SELECT extract(year  FROM date1)::int AS year
     , extract(month FROM date1)::int AS month
     , sum(spending)                  AS sum_spending
     , count(*)                       AS count_rows  -- optional
FROM   table
GROUP  BY 1, 2
HAVING count(*) > 1
ORDER  BY 1, 2;

1, 2 是（完全可选的）位置引用以缩短语法，因此我们不必重复 SELECT 列表中的表达式。示例：

Select first row in each GROUP BY group?

转换为整数 (::int) 也是可选的。通用 return 类型的提取是双精度的，但年份和日期可以安全地转换为整数。更小，更快，更充足。

Answer 3

试试这个

SELECT extract(year from date1), extract(month from date1), sum(spending)    
FROM ( SELECT *, COUNT(*) OVER(PARTITION BY CONCAT(extract(year FROM date1), extract(month FROM date1))) N
       FROM table) as A    
WHERE N > 1    
GROUP BY extract(year from date1),extract(month from date1)
ORDER BY extract(year from date1),extract(month from date1) ASC;

仅对具有多行的组求和值

Only sum values for groups with more than one row

sql

postgresql

aggregate

having