表的查找：

select * from emp where (sal>500 or job='MANAGER') and ename like 'J%';

引号里边的字符是区分大小写的。

查找之后把结果排序：

select * from emp order by sal asc;

asc是升序，desc是降序

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对列重命名，只要打个空格，后跟新列名就可以

select ename,sal*12+nvl(comm,0)*12 "年薪" from emp order by "年薪" asc;

此处的nvl是个小函数，如果comm是null的话，就用0代替

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最大最小值函数：

SQL> select max(sal) "maxSal",min(sal) "minSal" from emp;

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??? maxSal???? minSal?????????????????????????????????????????????? ????????????????????????????????????????????????????

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