mysql - 如何在mySQL中连接2行数据？

Question

我想将 2 行数据合并为 1 行。我尝试过寻找如何做到这一点，但我看到的都是不好的。

这是我的示例表

ID | Col1    | Col 2
=====================
1  | value11 | value12
2  | value12 | value22

这就是我想要实现的目标

ID | Col1    | Col 2   | Col21   | Col22
==========================================
1  | value11 | value12 | value12 | value22

请帮忙...提前致谢。

Answer 1

100 个样本之一

SELECT
 s1.id,
 s1.col1 AS c1,
 s1.col2 AS c2,
 s2.col1 AS c21,
 s2.col2 AS c22 
FROM sample_table AS s1 
LEFT JOIN sample_table AS s2 ON s1.id +1 = s2.id
WHERE s1.id = 1;