---取1到3位 SQL> select job,substr(job,1,3) from emp; JOB SUBSTR --------- ------ CLERK CLE SALESMAN SAL SALESMAN SAL MANAGER MAN SALESMAN SAL MANAGER MAN MANAGER MAN ANALYST ANA PRESIDENT PRE SALESMAN SAL CLERK CLE JOB SUBSTR --------- ------ CLERK CLE ANALYST ANA CLERK CLE 14 rows selected. ---取后2位 SQL> select job,substr(job,length(job)-1,length(job)) from emp; JOB SUBSTR(JOB,LENGTH( --------- ------------------ CLERK RK SALESMAN AN SALESMAN AN MANAGER ER SALESMAN AN MANAGER ER MANAGER ER ANALYST ST PRESIDENT NT SALESMAN AN CLERK RK JOB SUBSTR(JOB,LENGTH( --------- ------------------ CLERK RK ANALYST ST CLERK RK 14 rows selected.