如果有多个字段，则重复密钥更新

Question

INSERT INTO highscore(user, points, modality, time, level)
VALUES('$user', '$score', '$modality', '$time', '$level')

ON DUPLICATE KEY UPDATE
  points = IF(VALUES(points) > points, VALUES(points), points),
  time = IF(VALUES(points) > points, VALUES(time), time),
  level = IF(VALUES(points) > points, VALUES(level), level)

UNIQUE字段是“用户”和“模态”

此代码不起作用，如果old_points为> new_points，则此查询仅更新points字段。 当新点>旧时，我必须使用相应的值更新这3个字段。

怎么修 ？

Answer 1

用这个

points = IF(VALUES(points) > points, VALUES(points), points),
time = IF(VALUES(points) >= points, VALUES(time), time),
level = IF(VALUES(points) >= points, VALUES(level), level)

注意>=符号

解释：在第一行中， points的值已经改变

Answer 2

以下只是一个证明，你的代码很好，并完全按照你的期望。

mysql> select version();
+------------------------+
| version()              |
+------------------------+
| 5.1.41-3ubuntu12.7-log |
+------------------------+
1 row in set (0.00 sec)

---

 create table highscore(user int, points int, modality int, time int, level int, unique key idx_u_m (use                         r, modality));
Query OK, 0 rows affected (0.11 sec)

mysql> INSERT INTO highscore(user, points, modality, time, level)
    -> VALUES(1, 1, 1, 1, 1)
    -> ON DUPLICATE KEY UPDATE
    -> points = IF(VALUES(points) > points, VALUES(points), points),
    -> time = IF(VALUES(points) > points, VALUES(time), time),
    -> level = IF(VALUES(points) > points, VALUES(level), level);
Query OK, 1 row affected (0.01 sec)

mysql> INSERT INTO highscore(user, points, modality, time, level)
    -> VALUES(1, 1, 1, 1, 1)
    -> ON DUPLICATE KEY UPDATE
    -> points = IF(VALUES(points) > points, VALUES(points), points),
    -> time = IF(VALUES(points) > points, VALUES(time), time),
    -> level = IF(VALUES(points) > points, VALUES(level), level);
Query OK, 0 rows affected (0.15 sec)

mysql> select * from highscore;
+------+--------+----------+------+-------+
| user | points | modality | time | level |
+------+--------+----------+------+-------+
|    1 |      1 |        1 |    1 |     1 |
+------+--------+----------+------+-------+
1 row in set (0.00 sec)

mysql> INSERT INTO highscore(user, points, modality, time, level)
    -> VALUES(1, 2, 1, 1, 1)
    -> ON DUPLICATE KEY UPDATE
    -> points = IF(VALUES(points) > points, VALUES(points), points),
    -> time = IF(VALUES(points) > points, VALUES(time), time),
    -> level = IF(VALUES(points) > points, VALUES(level), level);
Query OK, 2 rows affected (0.09 sec)

mysql> select * from highscore;                                                                                                        +------+--------+----------+------+-------+
| user | points | modality | time | level |
+------+--------+----------+------+-------+
|    1 |      2 |        1 |    1 |     1 |
+------+--------+----------+------+-------+
1 row in set (0.00 sec)

mysql> INSERT INTO highscore(user, points, modality, time, level)
    -> VALUES(2, 2, 1, 1, 1)
    -> ON DUPLICATE KEY UPDATE
    -> points = IF(VALUES(points) > points, VALUES(points), points),
    -> time = IF(VALUES(points) > points, VALUES(time), time),
    -> level = IF(VALUES(points) > points, VALUES(level), level);
Query OK, 1 row affected (0.03 sec)

mysql> select * from highscore;
+------+--------+----------+------+-------+
| user | points | modality | time | level |
+------+--------+----------+------+-------+
|    1 |      2 |        1 |    1 |     1 |
|    2 |      2 |        1 |    1 |     1 |
+------+--------+----------+------+-------+
2 rows in set (0.00 sec)

mysql> INSERT INTO highscore(user, points, modality, time, level)
    -> VALUES(2, 3, 1, 1, 1)
    -> ON DUPLICATE KEY UPDATE
    -> points = IF(VALUES(points) > points, VALUES(points), points),
    -> time = IF(VALUES(points) > points, VALUES(time), time),
    -> level = IF(VALUES(points) > points, VALUES(level), level);
Query OK, 2 rows affected (0.08 sec)

mysql> select * from highscore;
+------+--------+----------+------+-------+
| user | points | modality | time | level |
+------+--------+----------+------+-------+
|    1 |      2 |        1 |    1 |     1 |
|    2 |      3 |        1 |    1 |     1 |
+------+--------+----------+------+-------+
2 rows in set (0.00 sec)