PHP使用相同的值回显id

Question

我有这张桌子

我想要做的是查询/回显那些具有相同值的id，例如id 1，id 3具有相同的值。这可能在同一个表格和列中吗？谢谢！

Answer 1

您可以使用自联接来获取具有相同权重的所有ID对

SELECT t1.weight, t1.id AS id1, t2.id AS id2
FROM YourTable AS t1
JOIN YourTable AS t2 ON t1.weight = t2.weight AND t1.id < t2.id

或GROUP_CONCAT在一行中获取具有相同权重的所有ID：

SELECT weight, GROUP_CONCAT(id) AS ids
FROM YourTable
GROUP BY weight
HAVING COUNT(*) > 1

每个体重只需一对：

SELECT t1.weight, t1.id AS id1, t2.id AS id2
FROM YourTable AS t1
JOIN YourTable AS t2 ON t1.weight = t2.weight AND t1.id < t2.id
GROUP BY t1.weight

DEMO