Question

我真的不知道如何搜索这个，可能它很容易做到，但我不知道如何做到这一点。我有一个SQL表：

| c1 | c2 | c3 | c4 | c5 |
 data data data data data

所以我有5列，现在我想选择只有以下（c1，c2，c3）的行，其中该行在表格中出现的次数超过5次像这样：

  Select c1, c2, c3 
  From table
  having count(*) > 5 and (all in that count, all rows must have the same values on c1, c2, c3)

只能通过基本的SQL查询来执行此操作。不允许使用函数，声明等。我真的不知道我是否能很好地解释自己。

Answer 1

我并不完全确定，但我的猜测是

select c1, c2, c3
from <yourtable>
group by c1, c2, c3
having count(*) > 5

Answer 2

此查询将返回原始表格中的所有记录，其中c1，c2和c3组合值的重复次数更多超过5次。我还在结果集中包含了实际计数。

SELECT t1.c1, t1.c2, t1.c3, t1.c4, t1.c5, t2.cardinality
FROM yourTable t1
INNER JOIN
(
    SELECT c1, c2, c3, COUNT(*) AS cardinality
    FROM yourTable
    GROUP BY c1, c2, c3
    HAVING COUNT(*) > 5
) t2
    ON t1.c1 = t2.c1 AND
       t1.c2 = t2.c2 AND
       t1.c3 = t2.c3

Answer 3

将c1，c2，c3视为单个字符串c1 + c2 + c3：

SELECT c1, c2, c3 FROM table WHERE
c1 || c2 || c3 IN (
  SELECT c1 || c2 || c3 FROM table
  GROUP BY c1 || c2 || c3
  HAVING COUNT(*) > 5);

SQL选择具有计数＆gt;的行一定数量

3 个答案: