SQL：更新初始表的多行总和

Question

以下内容不断给我错误，我已经确定它是组，但我不知道什么是错误的/如何修复。

t1

    c1 c2

    1 -

    2 -

t2

    c1 c2

    1 - 3

    1 - 2

    2 - 2

    2 - 2

    UPDATE T1 a, t2 b SET a.c2 = sum(b.c2)
    GROUP BY b.c1 HAVING b.c1 = a.c1;

Answer 1

你可以试试这个：

UPDATE T1
SET c2 = (SELECT SUM(c2) FROM T2 WHERE c1 = T1.c1)

Answer 2

试试这个：

      UPDATE T1
      set a.c2= b.c2 from T1 a inner JOIN 
     (select c1, sum(c2) from T2 group by c1) b on a.c1 = b.c1;

Answer 3

这个怎么样：

UPDATE a SET a.c2 = sum(b.c2)
FROM T1 a INNER JOIN t2 b ON a.c1 = b.c1     
GROUP BY b.c1