在Mysql中找到同一行内多列的重复值

Question

请帮助在MySQL中找到同一行多列中的重复条目：

Answer 1

如果要查找列中包含重复项的记录，可以使用此查询：

SELECT T1.* FROM tbl T1
JOIN  
    (SELECT id
    FROM (
        SELECT id, sample1 AS n from tbl
        UNION ALL
        SELECT id, sample2 AS n from tbl
        UNION ALL
        SELECT id, sample3 AS n from tbl
    ) AS X
    GROUP BY id, n
    HAVING COUNT(*) > 1
) T2
    ON T1.id = T2.id;

您还可以对其进行测试Here

Answer 2

我不确定MySql，

但是在下面的PHP示例中将使用。

示例

$query = "select * from table_name";
$result = mysqli_query($query);
while ($row = mysqli_fetch_array($result)) {
    if ($row['sample1'] == $row['sample2']) {
        // This row duplicate
    }
    else {
        // This row not duplicate
    }
}

Answer 3

SELECT Sample1, COUNT(*) C FROM tablename GROUP BY Sample1 HAVING C > 1;

Finding duplicate values in MySQL

MySQL select records for duplicates using multiple columns