Sql 如何将select语句写入这两列？

你能写一个SQL命令在这两列中帮助我吗

例如……这两列

a1             a2
______       ______
1              1
2              1
1              2
2              3
3              1
3              2
4              1
4              2

我想要输出：

a1 a1
1  2
2  3
3  2
4  2

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根据您的示例，我猜测您希望第二列是对应a1值的最大a2值

那么你想要：

SELECT a1, MAX(a2) AS a2 FROM table GROUP BY a1

---

根据您的示例，我猜测您希望第二列是对应a1值的最大a2值

那么你想要：

SELECT a1, MAX(a2) AS a2 FROM table GROUP BY a1

基本骨料：

SELECT a1, MAX(a2) AS a2
  FROM AnonymousTable
 GROUP BY a1;

基本骨料：

SELECT a1, MAX(a2) AS a2
  FROM AnonymousTable
 GROUP BY a1;