在销量增加中犯了同样的错误，一开始就认为是sql语句错了，结果就是这个逗号被直接忽略，在service层浪费了两个半钟。。。感谢啊，要是没你的提示还不知道要搞多久。

解决了，原来是没有删除

set stock = stock - #{amount}，

这的逗号

### Error updating database.  Cause: java.sql.SQLSyntaxErrorException: 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 'where item_id = 5 and stock >= 1' at line 3

### The error may involve defaultParameterMap

### The error occurred while setting parameters

### SQL: update item_stock     set stock = stock - 1,     where item_id = 5 and stock >= 1

### Cause: java.sql.SQLSyntaxErrorException: 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 'where item_id = 5 and stock >= 1' at line 3

; bad SQL grammar []; nested exception is java.sql.SQLSyntaxErrorException: 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 'where item_id = 5 and stock >= 1' at line 3]