我的kibana日志中出现错误，内容如下：
SELECT DISTINCT
company.company_id,
company.companyname_1,
customer.customer_id,
customer.customername_1,
DECODE(receipt.table_name, 'PAYMENT', SUM(COUNT(receipt.receipt_id))) as inpayment
FROM
company
JOIN customer ON company.company_id = customer.company_id
JOIN debtor ON customer.customer_id = debtor.customer_id
JOIN debtortrunk ON debtor.debtor_id = debtortrunk.debtor_id
JOIN receipt ON debtor.customer_id = receipt.customer_id AND debtor.deb_id = receipt.deb_id
WHERE
receipt.created >= '24.01.2018' AND
receipt.created <= '28.01.2018'
GROUP BY
company.company_id,
company.companyname_1,
customer.customer_id,
customer.customername_1
。我对措词感到有些困惑，因为我通常会在this.a.b is undefined中看到一个未定义的属性。
我使用此属性的唯一地方是为它分配一个值：cannot read property b of undefined-赋值可能是这种措辞的原因吗？
预先感谢
答案 0 :(得分：0)
没有看到您的代码： 编写这样的nullguard：
if( this && this.a && this.a.b) { /*do stuff*/}
以此确保您要执行操作的元素在那里。