文章目录

MySQL内置函数
1、日期函数
2、字符串函数
- 把EMP表中的所有名字中有S的替换为’云南’:
mysql> select replace(ename,'S','云南'),ename from EMP;
+-----------------------------+--------+
| replace(ename,'S','云南') | ename |
+-----------------------------+--------+
| 云南MITH | SMITH |
| ALLEN | ALLEN |
| WARD | WARD |
| JONE云南 | JONES |
| BLAKE | BLAKE |
| CLARK | CLARK |
| 云南COTT | SCOTT |
| KING | KING |
| TURNER | TURNER |
| ADAM云南 | ADAMS |
| JAME云南 | JAMES |
| FORD | FORD |
| MILLER | MILLER |
+-----------------------------+--------+
13 rows in set (0.00 sec)
mysql>
- 截取EMP表中ename中的第二个到第三个字符:
mysql> select substring(ename,2,2) , ename from EMP;
+----------------------+--------+
| substring(ename,2,2) | ename |
+----------------------+--------+
| MI | SMITH |
| LL | ALLEN |
| AR | WARD |
| ON | JONES |
| LA | BLAKE |
| LA | CLARK |
| CO | SCOTT |
| IN | KING |
| UR | TURNER |
| DA | ADAMS |
| AM | JAMES |
| OR | FORD |
| IL | MILLER |
+----------------------+--------+
13 rows in set (0.00 sec)
mysql>
- 以首字母小写的方式现实所有员工的姓名:
mysql> select concat(lcase(substring(ename,1,1)),substring(ename,2)),ename from
EMP;
+--------------------------------------------------------+--------+
| concat(lcase(substring(ename,1,1)),substring(ename,2)) | ename |
+--------------------------------------------------------+--------+
| sMITH | SMITH |
| aLLEN | ALLEN |
| wARD | WARD |
| jONES | JONES |
| bLAKE | BLAKE |
| cLARK | CLARK |
| sCOTT | SCOTT |
| kING | KING |
| tURNER | TURNER |
| aDAMS | ADAMS |
| jAMES | JAMES |
| fORD | FORD |
| mILLER | MILLER |
+--------------------------------------------------------+--------+
13 rows in set (0.00 sec)
mysql>
3、数学函数
4、其他函数
OKOK,MySQL内置函数就到这里,如果你对Linux和C++也感兴趣的话,可以看看我的主页哦。下面是我的github主页,里面记录了我的学习代码和leetcode的一些题的题解,有兴趣的可以看看。
Xpccccc的github主页