数学四则运算

　　　　　　　　　　　　　　　　　　　　　　　　　　四则运算符号

运算符	描述
+	加法
-	减法
*	乘法
/(DIV)	除法
%(MOD)	求余

 

 

 

 

 

【1】+加法用法

mysql> SELECT NAME,JOB,SALARY,SALARY+500 MONTHS_AWARD FROM employee_info;   #给每位员工每月奖励500元
+-------+----------+--------+-------------+
| NAME | JOB | SALARY | MONTHS_AWARD |
+-------+----------+--------+-------------+
| aly | salesman | 600 | 1100 |
| bob | agent | 1500 | 2000 |
| cindy | salesman | 800 | 1300 |
+-------+----------+--------+-------------+

【2】-减法用法

参照加法

【3】* 乘法用法

mysql> SELECT*FROM employee_info;
+------+-------+------+----------+--------+
| ID | NAME | AGE | JOB | SALARY |
+------+-------+------+----------+--------+
| 1001 | aly | 22 | salesman | 600 |
| 1002 | bob | 23 | agent | 1500 |
| 1003 | cindy | 21 | salesman | 800 |
+------+-------+------+----------+--------+
3 rows in set (0.00 sec)

mysql> SELECT NAME,JOB,SALARY*12 YEARS_SALARY   #显示一年的工资
-> FROM employee_info;
+-------+----------+--------------+
| NAME | JOB | YEARS_SALARY |
+-------+----------+--------------+
| aly | salesman | 7200 |
| bob | agent | 18000 |
| cindy | salesman | 9600 |
+-------+----------+--------------+

【4】/ 除法用法

mysql> SELECT NAME,JOB,SALARY,SALARY/30 DAY_SALARY FROM employee_info;   #计算每位员工的每天的薪水
+-------+----------+--------+------------+
| NAME | JOB | SALARY | DAY_SALARY |
+-------+----------+--------+------------+
| aly | salesman | 600 | 20.0000 |
| bob | agent | 1500 | 50.0000 |
| cindy | salesman | 800 | 26.6667 |
+-------+----------+--------+------------+

【5】设置显示格式

CONCAT(  )命令

mysql> SELECT CONCAT (NAME,'雇员的年薪为: ',SALARY*12) YEARS_SALARY FROM employee_info;
+-------------------------+
| YEARS_SALARY |
+-------------------------+
| aly雇员的年薪为: 7200 |
| bob雇员的年薪为: 18000 |
| cindy雇员的年薪为: 9600 |
+-------------------------+