接着PrestoDb，其中FirstField可以具有多个值：

Question

如何按查询计算组返回的记录数

例如：

select count(*) 
from temptable
group by column_1, column_2, column_3, column_4

给我，

1
1
2

我需要计算上述记录才能获得1 + 1 + 1 = 3。

Answer 1

您可以使用另一个COUNT

上的OVER子句在一个查询中执行这两个操作

select
    count(*) RecordsPerGroup,
    COUNT(*) OVER () AS TotalRecords
from temptable
group by column_1, column_2, column_3, column_4

Answer 2

最简单的解决方案是使用派生表：

Select Count(*)
From    (
        Select ...
        From TempTable
        Group By column_1, column_2, column_3, column_4
        ) As Z

另一种解决方案是使用Count Distinct：

Select ...
    , ( Select Count( Distinct column_1, column_2, column_3, column_4 )
        From TempTable ) As CountOfItems
From TempTable
Group By column_1, column_2, column_3, column_4

Answer 3

我知道现在已经很晚了，但没有人建议：

select count ( distinct column_1, column_2, column_3, column_4) 
from   temptable

这至少在Oracle中有效 - 我目前没有其他数据库可以测试它，我对T-Sql和MySQL语法不太熟悉。

另外，我不完全确定在解析器中以这种方式执行它是否更有效，或者是否其他人的嵌套select语句的解决方案更好。但是从编码的角度来看，我觉得这个更优雅。

Answer 4

我试图在没有子查询的情况下实现相同的目标，并且能够获得所需的结果，如下所示

SELECT DISTINCT COUNT(*) OVER () AS TotalRecords
FROM temptable
GROUP BY column_1, column_2, column_3, column_4

Answer 5

CTE为我工作：

with cte as (
  select 1 col1
  from temptable
  group by column_1
)

select COUNT(col1)
from cte;

Answer 6

怎么样：

SELECT count(column_1)
FROM
    (SELECT * FROM temptable
    GROUP BY column_1, column_2, column_3, column_4) AS Records

Answer 7

你可以这样做：

select sum(counts) total_records from (
    select count(*) as counts
    from temptable
    group by column_1, column_2, column_3, column_4
) as tmp

Answer 8

在PostgreSQL中，这对我有用：

select count(count.counts) 
from 
    (select count(*) as counts 
     from table 
     group by concept) as count;

Answer 9

您可以执行以下代码吗？它在Oracle中有效。

SELECT COUNT(COUNT(*))
FROM temptable
GROUP BY column_1, column_2, column_3, column_4

Answer 10

您也可以通过以下查询获取

select column_group_by,count(*) as Coulm_name_to_be_displayed from Table group by Column;

-- For example:
select city,count(*) AS Count from people group by city

Answer 11

尝试此查询：

select top 1 TotalRows = count(*) over () 
from yourTable
group by column1, column2

Answer 12

接着PrestoDb，其中FirstField可以具有多个值：

select *
            , concat(cast(cast((ThirdTable.Total_Records_in_Group * 100 / ThirdTable.Total_Records_in_baseTable) as DECIMAL(5,2)) as varchar), '%') PERCENTage
from 
(
    SELECT FirstTable.FirstField, FirstTable.SecondField, SecondTable.Total_Records_in_baseTable, count(*) Total_Records_in_Group
    FROM BaseTable FirstTable
    JOIN (
            SELECT FK1, count(*) AS Total_Records_in_baseTable 
            FROM BaseTable
            GROUP BY FK1
        ) SecondTable
    ON FirstTable.FirstField = SecondTable.FK1
    GROUP BY FirstTable.FirstField, FirstTable.SecondField, SecondTable.Total_Records_in_baseTable
    ORDER BY FirstTable.FirstField, FirstTable.SecondField
) ThirdTable

Answer 13

如何在SQL Server中使用COUNT OVER（PARTITION BY {column to group by}）分区功能？

例如，如果您想按ItemID对产品销售进行分组，并且您想要计算每个不同的ItemID，只需使用：

SELECT
{columns you want} ,
COUNT(ItemID) OVER (PARTITION BY ItemID) as BandedItemCount ,
{more columns you want}... ,
FROM {MyTable}

如果你使用这种方法，你可以将GROUP BY从图片中删除 - 假设你想要返回整个列表（因为你可能会报告条带，你需要知道你要去的所有项目的数量）乐队无需显示整套数据，即Reporting Services）。

计算按组返回的记录数

13 个答案:

接着PrestoDb，其中FirstField可以具有多个值：