列的拼接

使用||作为连接运算符

SQL> select ename||CHR(32)||CHR(32)||'WORK AS A '||job as msg from emp;

MSG
-------------------------------
SMITH  WORK AS A CLERK
ALLEN  WORK AS A SALESMAN
WARD  WORK AS A SALESMAN
JONES  WORK AS A MANAGER
MARTIN	WORK AS A SALESMAN
BLAKE  WORK AS A MANAGER
CLARK  WORK AS A MANAGER
SCOTT  WORK AS A ANALYST
KING  WORK AS A PRESIDENT
TURNER	WORK AS A SALESMAN
ADAMS  WORK AS A CLERK

MSG
-------------------------------
JAMES  WORK AS A CLERK
FORD  WORK AS A ANALYST
MILLER	WORK AS A CLERK

14 rows selected.

CHR(32)代表空格