Error querying database. Cause: java.sql.SQLException: ORA-01722: invalid number

我遇到的这个错误是sql在表连接的时候类型不匹配

select * from a
LEFT JOIN SDH5.T_BUSINESS_PRODUCT_CONFIG E
        ON
        a.COUNTCODE = E.B_ID

a.COUNTCODE 类型是varchar2类型
但是E.B_ID的类型是NUMBER类型
因而保错
解决方法：
number类型转字符串varchar2类型

select * from a
LEFT JOIN SDH5.T_BUSINESS_PRODUCT_CONFIG E
        ON
        a.COUNTCODE = to_char(E.B_ID)