ascii码:

https://img1.sycdn.imooc.com/6266ab5200010f8f06500681.jpg

转义字符

https://img3.sycdn.imooc.com/6266ab8400017b6a06500362.jpg

&& 前面为false 后面就不执行,& 全都执行

运算符优先级

https://img1.sycdn.imooc.com/6266ab950001070506500320.jpg

scanner方法:

https://img4.sycdn.imooc.com/6266abbe0001c8c706500541.jpg

dowhile 后面要有分号:

https://img1.sycdn.imooc.com/6266abdc0001d2e706500369.jpg

增强型for循环

https://img3.sycdn.imooc.com/6266ac2e000109a506500177.jpg

可变参数的方法参数列表

https://img4.sycdn.imooc.com/6266ac4e000195ef06500564.jpg

111

https://img4.sycdn.imooc.com/6266ac5b000108b206500334.jpg

https://img1.sycdn.imooc.com/6266ac690001ebdc06500321.jpg

https://img4.sycdn.imooc.com/6266ac7000019fc206500343.jpg

https://img4.sycdn.imooc.com/6266ac7900016d2406500261.jpg

https://img3.sycdn.imooc.com/6266ac81000137b806500637.jpg

https://img1.sycdn.imooc.com/6266ac8e0001172a06500390.jpg

数据库阶段:::

https://img1.sycdn.imooc.com/6266acf8000124e306500575.jpg

https://img4.sycdn.imooc.com/6266acff0001a09e06500360.jpg

https://img1.sycdn.imooc.com/6266ad3f0001ecae06500375.jpg

https://img4.sycdn.imooc.com/6266ad460001934706500621.jpg

https://img1.sycdn.imooc.com/6266ad4e0001abe806500341.jpg

https://img2.sycdn.imooc.com/6266ad53000133e406500392.jpg

好吧::

https://img1.sycdn.imooc.com/climg/6265fccf098c97f707460433.jpg

::

https://img1.sycdn.imooc.com/climg/6266073b0964872306990438.jpg

https://img1.sycdn.imooc.com/climg/626607590972ef2f08640392.jpg

https://img1.sycdn.imooc.com/climg/6266085509fd69eb06870411.jpg

https://img1.sycdn.imooc.com/climg/626613600929c57907750275.jpg

https://img1.sycdn.imooc.com/climg/626613b509ff632c10730584.jpg

https://img1.sycdn.imooc.com/climg/6266141709c0b04707310383.jpg

https://img1.sycdn.imooc.com/climg/6266409a09c7db1810440659.jpg

https://img1.sycdn.imooc.com/climg/62664204097d301a00000000.jpg

https://img1.sycdn.imooc.com/climg/626642dc092a0de212270659.jpg

https://img1.sycdn.imooc.com/climg/6266430e09fcff0a07170348.jpg

https://img1.sycdn.imooc.com/climg/6266449a09bc23bb07270207.jpg

https://img1.sycdn.imooc.com/climg/626644f40974c6b304600346.jpg

https://img1.sycdn.imooc.com/climg/6266453009598ed208850565.jpg

https://img1.sycdn.imooc.com/climg/6266454e092efa5410330529.jpg

https://img1.sycdn.imooc.com/climg/626646ee09a563ea12910607.jpg

https://img1.sycdn.imooc.com/climg/6266471809087f3d08160563.jpg

聚合函数 共有五个: sum()  max()  min()   avg()   count() 

https://img1.sycdn.imooc.com/climg/626691a009812dc512730697.jpg

https://img1.sycdn.imooc.com/climg/6266926009abcfbd12000646.jpg

将符合条件的分组查询拼接成字符串

https://img1.sycdn.imooc.com/climg/626692ff096d9ebd07450400.jpg

https://img1.sycdn.imooc.com/climg/6266933209aaf1f407860365.jpg

https://img1.sycdn.imooc.com/climg/62669488097659d007290250.jpg

https://img1.sycdn.imooc.com/climg/6266972b098b803709520478.jpg

https://img1.sycdn.imooc.com/climg/6266978b09be394208040424.jpg

https://img1.sycdn.imooc.com/climg/626697d60962d7a308040419.jpg

外连接   保留不符合的数据(左外连接 保留左表的数据,右外连接 保留右表的数据)

https://img1.sycdn.imooc.com/climg/62669b110923024a13010687.jpg

https://img1.sycdn.imooc.com/climg/62669c03099212b112240372.jpg

作者:|彭于晏上海分晏|,原文链接: http://www.imooc.com/article/325178

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