我是 Java 世界的新手。我对简单查询有疑问:
<insert id="create" parameterType="models.entities.CategoryEntity">
set @catId := (select categoryId from Categories limit 1);
insert into Categories(CategoryId, Title, LeftValue, RightValue)
values(@catId, 'Test in', 1,2);
....
</insert>
当我尝试使用 mybatis 运行它时,它就失败了:
PersistenceException occured : ### Error updating database. Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: 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 'insert into Categories(CategoryId, Title, LeftValue, RightValue) values(' at line 2 ### The error may involve Category.create-Inline ### The error occurred while setting parameters ### Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: 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 'insert into Categories(CategoryId, Title, LeftValue, RightValue) values(' at line 2
如果我删除这一行:
set @catId := (select categoryId from Categories limit 1);
那么一切都好。我究竟做错了什么?是jdbc还是mybatis的问题?如何在 mybatis 中使用 mysql @variables?有人有在 mybatis 中使用 MySql 局部变量的例子吗?