我需要计算 A 列中有重复记录的行数，B 列必须为 1 并且也必须重复。
SELECT COUNT(*) as num
FROM myTable
WHERE (columnB = 1 GROUP BY columnB HAVING COUNT(id_myTable) > 1) AND (columnA IN (SELECT columnA FROM myTable GROUP BY columnA HAVING COUNT(id_myTable) > 1))
ORDER BY columnC ASC`
假设您在 MySQL 中有这些名为 myTable 的表:
/---------------------------------/
| id | ColumnA | Column B |
|---------------------------------|
| 1 | Andre | 1 |
| 2 | Joao | 2 |
| 3 | Maria | 1 |
| 4 | Joao | 1 |
| 5 | Andre | 1 |
| 6 | Maria | 1 |
| 7 | Andre | 2 |
/---------------------------------/
结果必须是 4，因为只有 id 1、3、5 和 6 的两列都是重复的，并且 columnB 的条件必须始终等于 1。
我的 PHP 代码给出结果:
$query = "select sum(c) from (select count(1) as c from myTable group by columnA, columnB having count(1) > 1 and columnB = 1) t";
$total_pages = mysql_fetch_array(mysql_query($query));
$total_pages = $total_pages[c];
$total_rows = $total_pages;
最佳答案
select sum(c) from (
select count(1) as c from myTable
group by ColumnA, ColumnB
having count(1) > 1 and ColumnB=1
) t
关于MySQL查询以在两列中显示重复项，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/46864836/