MySQL COUNT（），SUM（）和GROUP BY

Question

我有一个关于MySQL的特殊问题。请看看查询和结果设置如下：

SELECT COUNT(c.Population) AS c, c.City AS cc 
FROM City c 
GROUP BY c.City 
ORDER BY c.City; 

261 | Bristol 
---------------- 
910 | London 
---------------- 
241 | Manchester 
---------------- 

我想获得计数的总和，所以在这种情况下，我想看看“ 1412'在下一行，或在一个新的专栏中，这并不重要。

有什么建议吗？我试图应用子查询，但我找不到合适的解决方案。

干杯

Answer 1

在select语句，这应该工作（未经测试）。

SELECT 
    COUNT(c.Population) AS c, 
    c.City AS cc, 
    (SELECT COUNT(c.Population) FROM City) as TotalPop 
FROM City c 
GROUP BY c.City 
ORDER BY c.City; 

Answer 2

是否WITH ROLLUP做你所需要的？

SELECT 
     COUNT(c.Population) AS c, 
     c.City AS cc 
FROM City c 
GROUP BY c.City 
WITH ROLLUP; 

Answer 3

在末一行：

SELECT * 
    FROM 
(
    SELECT 0 as total 
     , COUNT(c.Population) AS c 
     , c.City AS cc 
     FROM City c GROUP BY c.City 

    union 

    SELECT 1 as total 
     , COUNT(c.Population) AS c 
     , null AS cc 
     FROM City 
) myquery 
ORDER BY total 
     , city 

ORDER BY c.City;

Answer 4

用简单的UNION;

select count(d.Population) as c, 'TOTAL' as cc from City d 

union 

SELECT COUNT(c.Population) AS c, c.City AS cc 
FROM City c 
GROUP BY c.City 
ORDER BY c.City; 

约翰