SQL最大值形式count（）

Question

我有以下查询：

SELECT BusID, count(BusID) as 'NoofConnections'
FROM mytable
Group By BusID
Order by BusID

我得到下表：

BusID   NoofConnections
=========================
1       6
2       6
4       3
5       2
3       1

而且我将从NoofConnections中选择最大值，因此在这种情况下，LIMIT 1不起作用，因此我们有两个相等的值。 像这样：

 BusID   NoofConnections
=========================
1            6
2            6

有什么想法吗？

Answer 1

您可以使用子查询：

SELECT BusID, COUNT(*) as NoofConnections
FROM mytable
GROUP BY BusID
HAVING COUNT(*) = (SELECT COUNT(*)
                   FROM mytable
                   GROUP BY BusID
                   ORDER BY COUNT(*) DESC
                   LIMIT 1
                  )
ORDER BY BusID;

Answer 2

您可以使用子选择

  select * from (
    SELECT BusID, count(BusID) as NoofConnections
    FROM mytable
    Group By BusID

  )  t1 
  where t1.NoofConnections = (  select max(NoofConnections)
      from (
      SELECT BusID, count(BusID) as NoofConnections
      FROM mytable
      Group By BusID
      )