如何return只统计一列的结果？

Question

我有一个 table 这样的：

并且想按时间段（日期字段）创建一个 selection，我可以在其中 return 寄存器，并且一列寄存器总数仅与一列匹配。

例如：如果我使用这个查询：

SELECT date, product_type, operation, unit
FROM table
WHERE date BETWEEN '2019-08-26 00:00:00' AND '2019-08-26 23:59:59';

必须return:

但我希望我可以 return 多一列，总操作数不分周期，如下所示：

在这种情况下，6 是 "ajoy" 在 table 中出现的频率。

重要！如果我 select 有两个或多个操作被 returned，那么查询也必须能够 return 它们的频率。

Answer 1

我使用了您的部分数据，并将在 table 中包含我所拥有的数据，但我相信这就是您想要的

create table mytab (job int, operations char(8), prod char(8),  
ts_date datetime year to minute, unit int) lock mode row;

insert into mytab values(22, "ajoy","arrow","2020-05-11 08:51", 20);
insert into mytab values(22, "ajoy","arrow","2020-05-11 08:51", 20);
insert into mytab values(22, "ajoy","arrow","2020-05-11 08:51", 20);

insert into mytab values(22, "ajoy","arrow","2020-04-11 14:15", 20);
insert into mytab values(22, "ajoy","arrow","2020-04-11 14:15", 20);
insert into mytab values(22, "ajoy","arrow","2020-04-11 14:15", 20);

insert into mytab values(23, "dinn","curve","2020-05-11 08:51",1);
insert into mytab values(23, "dinn","point","2020-05-11 08:51",1);
insert into mytab values(23, "dinn","arrow","2020-04-11 08:51",1);

查询：

select job, operations, prod, ts_date, unit, (select count(*) from mytab b 
where b.operations = a.operations) total_operation  from mytab a where 
a.ts_date between "2020-05-11 08:50" and "2020-05-11 08:59"

上面的查询给了我以下结果，我认为这是你要的：

    job operations prod     ts_date                 unit  total_operation

     22 ajoy       arrow    2020-05-11 08:51          20                6
     22 ajoy       arrow    2020-05-11 08:51          20                6
     22 ajoy       arrow    2020-05-11 08:51          20                6
     23 dinn       curve    2020-05-11 08:51           1                3
     23 dinn       point    2020-05-11 08:51           1                3

此示例很小，没有 include/account 索引，您可以将其放在 table 上以加快查询性能。

如何return只统计一列的结果？

How to return a count result of only one column?

informix

select

frequency