MySQL从另一个表中更新表的值

Question

我有两个表，分别为finance_mpc_budget和finance_mpc_issues。他们加入并符合以下条件-

finance_mpc_budget.mpc_budget_id = finance_mpc_issues.ref_no

因此，我需要使用

更新finance_mpc_issues.ref_no

finance_mpc_budget.mpc_budget_id where finance_mpc_budget.mpc_budget_id > 55

为此，我使用了以下查询

UPDATE finance_mpc_issues 
JOIN (
      SELECT mpc_budget_id FROM finance_mpc_budget
      WHERE finance_mpc_budget.mpc_budget_id > 55 
      ORDER BY mpc_budget_id) a 
ON a.mpc_budget_id = finance_mpc_issues.ref_no 
SET finance_mpc_issues.ref_no = a.mpc_budget_id

但是它生成了空结果集。可能是错的。谁能帮我吗？

finance_mpc_budget表

+---------------+----------+--------+
| mpc_budget_id | category | amount |
+---------------+----------+--------+
|             56| A        |  22000 |
|             57| B        |  25000 |
|             58| C        |  45000 |
|             59| D        |  16000 |
+---------------+----------+--------+

finance_mpc_issues表

+-----------+--------+--------+
| issues_id | ref_no | amount |
+-----------+--------+--------+
|        10 |        |  22000 |
|        11 |        |  25000 |
|        12 |        |  45000 |
|        13 |        |  16000 |
+-----------+--------+--------+

所需的输出

+-----------+--------+--------+
| issues_id | ref_no | amount |
+-----------+--------+--------+
|        10 |      56|  22000 |
|        11 |      57|  25000 |
|        12 |      58|  45000 |
|        13 |      59|  16000 |
+-----------+--------+--------+

Answer 1

您可以在下面尝试-

update finance_mpc_issues 
join finance_mpc_budget a on a.mpc_budget_id = finance_mpc_issues.ref_no
set  finance_mpc_issues.ref_no=a.mpc_budget_id
where a.mpc_budget_id >55

Answer 2

您不能join使用ref_no，因为它为空。因此，您的finance_mpc_issues表未更新。

根据您的表和数据，我假定 amount列具有相同的值。因此，使用amount列可以得到所需的输出。

Update finance_mpc_issues fi
set fi.ref_no = 
  (select fb.mpc_budget_id 
     from finance_mpc_budget fb 
     WHERE fb.amount = fi.amount
  );

fiddle link