用户表是scott用户下的emp表:
问题时这样的:查询在1981年入职的所有员工
我用模糊查询做的
select * from emp where hiredate like '%81%';
但是如果我改成
select * from emp where hiredate like '%981%';或者
select * from emp where hiredate like '1981%';或者
select * from emp where hiredate like '_981%';
就差不出任何记录
为什么呢?
SQL> select * from emp where hiredate like '%981%';
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO
----- ---------- --------- ----- ----------- --------- --------- ------
SQL> select * from emp where hiredate like '%81%';
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO
----- ---------- --------- ----- ----------- --------- --------- ------
7499 ALLEN SALESMAN 7698 1981-2-20 1600.00 300.00 30
7521 WARD SALESMAN 7698 1981-2-22 1250.00 500.00 30
7566 JONES MANAGER 7839 1981-4-2 2975.00 20
7654 MARTIN SALESMAN 7698 1981-9-28 1250.00 1400.00 30
7698 BLAKE MANAGER 7839 1981-5-1 2850.00 30
7782 CLARK MANAGER 7839 1981-6-9 2450.00 10
7839 KING PRESIDENT 1981-11-17 5000.00 10
7844 TURNER SALESMAN 7698 1981-9-8 1500.00 0.00 30
7900 JAMES CLERK 7698 1981-12-3 950.00 30
7902 FORD ANALYST 7566 1981-12-3 3000.00 20
10 rows selected