如何对别名列表sql进行求和

Question

我有查询sql

select date_format(created_at,'%Y-%m-%d') as date,
(select count(*)  from tb_media where date_format(created_at,'%Y-%m-%d') = date ) as total
from tb_media group by date

结果：

如何总结科隆总数？

Answer 1

此查询应该有效：

select sum(a.total) from (
select date_format(created_at,'%Y-%m-%d') as date,
(select count(*)  from tb_media where date_format(created_at,'%Y-%m-%d') = date ) as total
from tb_media group by date) as a

Answer 2

嗯，您有2个可能的查询。简单的一个（如果你想要总计，你不需要其余的查询）：

SELECT COUNT(*) FROM tb_media

不那么简单：

SELECT SUM(t.total)
FROM (select date_format(created_at,'%Y-%m-%d') as date,
(select count(*)  from tb_media where date_format(created_at,'%Y-%m-%d') = date ) as total
from tb_media group by date) AS t;

Answer 3

如果我了解您的要求，那么您需要根据日期明智地计算记录，并且希望他们的总和在最后，您的created_on列是日期类型。如果它是正确的，那么您可以使用以下查询 -

SELECT IFNULL(DATE_FORMAT(created_at,'%Y-%m-%d'),'Total') AS rep_date, 
COUNT(*) total  FROM tb_media 
GROUP BY created_at WITH ROLLUP;

Answer 4

你可以尝试这个伴侣：

SELECT
    DATE_FORMAT(created_at, '%Y-%m-%d') AS `date`,
    COUNT(<put_table_key_here>) AS `total`
FROM
    tb_media
GROUP BY
    `date`;  

注意

• 使用表中的主键或任何键来计算所述记录
• Atleast，避免在脚本中出现性能时使用子查询

Answer 5

不确定您想要输出数据的内容或方式，但我最好的猜测是您想要一个列表，其中包含日期和每天的计数以及表格末尾的总和？ 如果是这样，这将有效：

(select date_format(created_at,'%Y-%m-%d') as date,count(*) 
from tb_media group by date) 
union
(select 'Total',count(*) from tb_media)

或者如果您只想要所有记录的总和，则查询将是

SELECT COUNT(*) FROM tb_media