我在寻找一个非常复杂的连接的解决方案时发现了这个问题。这是另一种解决方案，一个更复杂的问题，我认为可能有用。

我需要填充活动表中的product_id字段，其中活动以单位编号，单位以级别编号(使用字符串??N标识)，这样就可以使用SKU(即L1U1A1)标识活动。然后将这些sku存储在另一个表中。

我确定了以下内容以获得activity_id与product_id的列表:-

SELECT a.activity_id, w.product_id 
  FROM activities a 
  JOIN units USING(unit_id) 
  JOIN product_types USING(product_type_id) 
  JOIN web_products w 
    ON sku=CONCAT('L',SUBSTR(product_type_code,3), 'U',unit_index, 'A',activity_index)

我发现这是太复杂，以纳入一个SELECT在mysql，所以我创建了一个临时表，并加入了更新语句:-

CREATE TEMPORARY TABLE activity_product_ids AS (<the above select statement>);

UPDATE activities a
  JOIN activity_product_ids b
    ON a.activity_id=b.activity_id 
  SET a.product_id=b.product_id;

我希望有人觉得这有用

对于同一张表，

UPDATE PHA_BILL_SEGMENT AS PHA,
     (SELECT BILL_ID, COUNT(REGISTRATION_NUMBER) AS REG 
       FROM PHA_BILL_SEGMENT
        GROUP BY REGISTRATION_NUMBER, BILL_DATE, BILL_AMOUNT
        HAVING REG > 1) T
    SET PHA.BILL_DATE = PHA.BILL_DATE + 2
 WHERE PHA.BILL_ID = T.BILL_ID;

简单的MySQL:

UPDATE users AS U1, users AS U2 
SET U1.name_one = U2.name_colX
WHERE U2.user_id = U1.user_id

您可以像这样使用内部连接从另一个表更新值

UPDATE [table1_name] AS t1 INNER JOIN [table2_name] AS t2 ON t1.column1_name] = t2.[column1_name] SET t1.[column2_name] = t2.column2_name];

跟随这里了解如何使用这个查询http://www.voidtricks.com/mysql-inner-join-update/

或者您可以使用select作为子查询来完成此操作

UPDATE [table_name] SET [column_name] = (SELECT [column_name] FROM [table_name] WHERE [column_name] = [value]) WHERE [column_name] = [value];

查询详情请参见http://www.voidtricks.com/mysql-update-from-select/

UPDATE 
  receipt_invoices dest,
  (
    SELECT 
      `receipt_id`,
      CAST((net * 100) / 112 AS DECIMAL (11, 2)) witoutvat 
    FROM
      receipt 
    WHERE CAST((net * 100) / 112 AS DECIMAL (11, 2)) != total 
      AND vat_percentage = 12
  ) src 
SET
  dest.price = src.witoutvat,
  dest.amount = src.witoutvat 
WHERE col_tobefixed = 1 
  AND dest.`receipt_id` = src.receipt_id ;

希望这将帮助你在一个情况下，你必须匹配和更新两个表。

实际上你有两种方法:

MySQL更新连接语法:

UPDATE tableA a
INNER JOIN tableB b ON a.name_a = b.name_b
SET validation_check = if(start_dts > end_dts, 'VALID', '')
-- where clause can go here

ANSI SQL语法:

UPDATE tableA SET validation_check = 
    (SELECT if(start_DTS > end_DTS, 'VALID', '') AS validation_check
        FROM tableA
        INNER JOIN tableB ON name_A = name_B
        WHERE id_A = tableA.id_A)

挑一个对你来说最自然的。