摘要:
```sql
SELECT date_format(DATE(a.date_created),'%Y-%c-%d') As dateCreate, SUM(a.sm) As sumAmount, sum(orderCount) as countSum FROM (SELECT date_created, sum(amount) AS sm, count(... 阅读全文
摘要:
1.将json对象转化为json字符串,再判断该字符串是否为"{}" var data = {}; var b = (JSON.stringify(data) == "{}"); alert(b);//true 2.for in 循环判断 var obj = {}; var b = function 阅读全文