SQL 별칭 부여하기

@계산부분에 대한 컬럼명을 별칭으로 변경
SQL> select empno, ename, sal, comm, sal*12+comm as totalsal
  2  from emp;

@ 주의사항. (금지)
SQL> select ename job, sal
  2  from emp;
//as 없이도 별칭을 붙여줄순있지만 하지않는게 좋음.


@  별칭 as 주의사항
SQL> select ename as "full name", job, sal
  2  from emp;
//as 띄어쓰기를 할때 큰 따옴표로 표현


@  별칭 as 주의사항
SQL> select ename as "이름", job as "직책", sal as "급여"
  2  from emp;
//한글도 가능하다

SQL> select deptno as "부서번호", dname as "부서명"
 from edpt;

@  자료 사이에 띄어쓰기나 문장 출력
SQL> select empno||' ' || ename|| ' is ' || job
  2  from emp;

@
SQL> select empno||' '||ename||' job is '||job as sawon
  2  from emp;

@ q'[ 내용 ] 표시
SQL> select ename|| q'['s is job]' as info from emp;

@ 중복을 제거하기위한 distinct
SQL> select distinct deptno
  2  from emp;