SQLite的选择最常见

Question

该表是这样的：

A  B 
---------- 
John  a 
John  a 
Peter a 
Mary  b 
Ann  b 
Ann  b 

我想要的结果是B组和A全选最常见的词：

A  B 
---------- 
John  a 
Ann  b 

Answer 1

首先我计算的数量B，A组合，然后根据BI计算最大数量（MaxN），最后在外部查询中再次计算计数，但仅显示具有以下几行的行：maxN=COUNT(*)：

SELECT t.B, t.A, COUNT(*) as N 
FROM Table t LEFT JOIN 
(SELECT B, MAX(N) AS MaxN 
FROM (
    SELECT B, A, count(*) as N 
    FROM Table 
    GROUP BY B, A) as c 
GROUP BY B) as mx on t.B=mx.B 
GROUP BY t.B, t.A 
HAVING mx.MaxN=COUNT(*);