Question

我正在尝试使用子查询中多列的数据连续更新一行中的多列。

以下方法对我不起作用，我找不到适合我需要的方法：

UPDATE
    beers,
    (SELECT AVG(appearance) AS appearance, AVG(palate) AS palate, AVG(taste) AS taste, AVG(aroma) AS aroma, AVG(overall) AS overall, beer_id FROM reviews) AS review_total
SET
    beers.appearance = review_total.appearance, 
    beers.palate = review_total.palate, 
    beers.taste = review_total.taste, 
    beers.aroma = review_total.aroma, 
    beers.overall = review_total.overall
WHERE
    review_total.beer_id = beers.id
AND
    beers.id = 43

我没有收到这个错误，但有5个警告并且行没有更新：

Query OK, 0 rows affected, 5 warnings (0.01 sec)

显示警告给了我：

+-------+------+----------------------------------------------------+
| Level | Code | Message                                            |
+-------+------+----------------------------------------------------+
| Note  | 1265 | Data truncated for column 'appearance' at row 9991 |
| Note  | 1265 | Data truncated for column 'palate' at row 9991     |
| Note  | 1265 | Data truncated for column 'taste' at row 9991      |
| Note  | 1265 | Data truncated for column 'aroma' at row 9991      |
| Note  | 1265 | Data truncated for column 'overall' at row 9991    |
+-------+------+----------------------------------------------------+

我知道这个问题与数据类型有关，但数据类型是浮点数，我相信这也是AVG的结果：

mysql> describe beers;
+-------------+---------------+------+-----+---------+----------------+
| Field       | Type          | Null | Key | Default | Extra          |
+-------------+---------------+------+-----+---------+----------------+
| id          | int(11)       | NO   | PRI | NULL    | auto_increment |
| name        | varchar(90)   | YES  |     | NULL    |                |
| aroma       | float         | YES  |     | NULL    |                |
| appearance  | float         | YES  |     | NULL    |                |
| palate      | float         | YES  |     | NULL    |                |
| taste       | float         | YES  |     | NULL    |                |
| overall     | float         | YES  |     | NULL    |                |
+-------------+---------------+------+-----+---------+----------------+

下一个查询略有不同：

UPDATE
    beers
SET
    beers.appearance = review_total.appearance, 
    beers.palate = review_total.palate, 
    beers.taste = review_total.taste, 
    beers.aroma = review_total.aroma, 
    beers.overall = review_total.overall
FROM
    INNER JOIN (SELECT AVG(appearance) AS appearance, AVG(palate) AS palate, AVG(taste) AS taste, AVG(aroma) AS aroma, AVG(overall) AS overall, beer_id FROM reviews) review_total ON review_total.beer_id = beers.id
WHERE
    beers.id = 43

我得到的错误是：

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'FROM INNER JOIN (SELECT AVG(appearance) AS appearance, AVG(palate) AS palate, AV' at line 9

我真的找不到办法让这个工作，我希望有人看到我做错了什么。非常感谢你提前！

Answer 1

  UPDATE beers b
    JOIN 
       ( SELECT beer_id
              , AVG(appearance) appearance
              , AVG(palate) palate
              , AVG(taste) taste
              , AVG(aroma) aroma
              , AVG(overall) overall
              , beer_id 
           FROM reviews
          GROUP
             BY beer_id
       ) review_total 
      ON review_total.beer_id = b.id
     SET b.appearance = review_total.appearance
       , b.palate = review_total.palate
       , b.taste = review_total.taste
       , b.aroma = review_total.aroma
       , b.overall = review_total.overall
   WHERE b.id = 43;

或类似的东西

使用MySQL中子查询的数据更新多个列

1 个答案: