on子句MySQL中的未知列

我想访问MySQL子查询中的一个字段，但在“on子句”中得到一个未知列

“var\u customer\u id”

错误。这是我的代码：

SELECT *,
        CONCAT(customer_phone_1, ', ', customer_phone_2) AS customer_phone,
        CONCAT(customer_fax_1, ', ', customer_fax_2) AS customer_fax,
        CONCAT(customer_email_1, ', ', customer_email_2) AS customer_email,
        tbl_customer.customer_id AS var_customer_id,                
        (
            SELECT
                GROUP_CONCAT(tbl_service.service_name SEPARATOR ', ')
            FROM
                kuesioner_bbia.tbl_customer_service
                INNER JOIN kuesioner_bbia.tbl_service 
                ON (tbl_customer_service.service_id = tbl_service.service_id )
                AND tbl_customer_service.customer_id=var_customer_id                    
            GROUP BY tbl_customer_service.customer_id                   
            )               

        FROM tbl_customer
        ORDER BY customer_id ASC

那么如何修复它呢？对不起，我的英语不好。

错误在这里：

ON (tbl_customer_service.service_id = tbl_service.service_id )
                AND tbl_customer_service.customer_id=var_customer_id   

它可以是以下内容之一（注意：我将

var\u customer\u id

替换为

tbl\u customer.customer\u id

）：

或（重新定位右括号）：

---

用一个合适的值替换var\u customer\u id。这可能是一个变量。您必须通过任何编程语言构建sql。

ON (tbl_customer_service.service_id = tbl_service.service_id )
WHERE tbl_customer_service.customer_id = tbl_customer.customer_id

ON (tbl_customer_service.service_id = tbl_service.service_id 
AND tbl_customer_service.customer_id = tbl_customer.customer_id)