我有这张叫做 chara 的桌子：
+----------+------------+----------------+-------------+------------+----------+----------+--------------+--------------+-----------+-----------+
| chara_id | chara_name | chara_class_id | chara_level | chara_gold | chara_hp | chara_mp | chara_max_hp | chara_max_mp | chara_atk | chara_def |
+----------+------------+----------------+-------------+------------+----------+----------+--------------+--------------+-----------+-----------+
| 1 | LawrenceX | 1 | 1 | 0 | 11610 | 1000 | 0 | 0 | 7 | 3 |
| 2 | Testo | 3 | 1 | 0 | 11465 | 900 | 0 | 0 | 9 | 1 |
| 3 | Viscocent | 2 | 1 | 0 | 11570 | 1100 | 0 | 0 | 5 | 5 |
| 4 | Piatos | 1 | 1 | 0 | 12470 | 1000 | 0 | 0 | 7 | 3 |
| 5 | Hello | 1 | 1 | 0 | 12600 | 1000 | 0 | 0 | 2 | 8 |
| 6 | Sample | 3 | 1 | 0 | 12700 | 900 | 0 | 0 | 9 | 1 |
| 7 | tester | 2 | 1 | 0 | 12500 | 1100 | 0 | 0 | 5 | 5 |
| 8 | Sampuro | 0 | 1 | 0 | 11700 | 100 | 0 | 0 | 5 | 5 |
+----------+------------+----------------+-------------+------------+----------+----------+--------------+--------------+-----------+-----------+
我有这个 chara_base_stat 表：
+--------------+----------------+------------------+---------------+---------------+----------------+----------------+
| base_stat_id | chara_class_id | chara_base_level | chara_base_hp | chara_base_mp | chara_base_atk | chara_base_def |
+--------------+----------------+------------------+---------------+---------------+----------------+----------------+
| 1 | 1 | 1 | 1000 | 1000 | 5 | 5 |
| 2 | 1 | 2 | 1100 | 1100 | 10 | 10 |
| 3 | 1 | 3 | 1200 | 1200 | 15 | 15 |
| 4 | 1 | 4 | 1300 | 1300 | 20 | 20 |
| 5 | 1 | 5 | 1400 | 1400 | 25 | 25 |
| 6 | 2 | 1 | 900 | 1100 | 7 | 3 |
| 7 | 2 | 2 | 1000 | 1200 | 14 | 6 |
| 8 | 2 | 3 | 1100 | 1300 | 21 | 9 |
| 9 | 2 | 4 | 1200 | 1400 | 28 | 12 |
| 10 | 2 | 5 | 1300 | 1500 | 35 | 19 |
| 11 | 3 | 1 | 1100 | 900 | 2 | 8 |
| 12 | 3 | 2 | 1200 | 1000 | 4 | 16 |
| 13 | 3 | 3 | 1300 | 1100 | 6 | 24 |
| 14 | 3 | 4 | 1400 | 1200 | 8 | 32 |
| 15 | 3 | 5 | 1500 | 1300 | 16 | 40 |
+--------------+----------------+------------------+---------------+---------------+----------------+----------------+
我有这个脚本每分钟更新一次 hp 的值（在这里使用 cronjob）：
$sql = "UPDATE chara SET chara_hp = chara_hp +100";
$stmt = $db->prepare($sql);
$stmt->execute();
我的挣扎：
我如何将 +100 添加到 chara 表中 chara_hp 的当前值，其中 chara 表中的当前 chara_hp 不超过 chara_base_stat 表中的 chara_base_hp
基本上我想要的只是在当前 hp 小于 chara_base_stat 表中的当前 chara_base_hp 时才重新生成那些玩家的 hp
注意：当前的chara_base_hp对应玩家当前的等级和玩家的chara_class_id。
到目前为止，我在这里有这个查询：
SELECT ch.chara_hp, bs.chara_base_hp FROM chara ch inner join chara_base_stat bs on(ch.chara_class_id = bs.chara_class_id and ch.chara_level = bs.chara_base_level)
返回
+----------+---------------+
| chara_hp | chara_base_hp |
+----------+---------------+
| 13210 | 1000 |
| 14070 | 1000 |
| 14200 | 1000 |
| 13170 | 900 |
| 14100 | 900 |
| 13065 | 1100 |
| 14300 | 1100 |
+----------+---------------+
我想在 sql 中执行此操作：
if(chara_hp < chara_base_hp){ update chara set chara_hp = chara_hp + 100 }