Linux学习-SQL之SQL语句

Posted 2021-06-30 丢爸

DML(Data Mainpulate Language):
DELETE
INSERT INTO
UPDATE
需先进行查询后，方可进行以上操作

INSERT INTO tb_name(col1,col2…,)values(val1,val2,…)[,(val1,val2,…),…]
字符型：必须使用单引号
数值型：不需要引号
日期时间型：不需要引号
空值：NULL
REPLACE INTO 使用方法同INSERT INTO,出现重复数据则直接替换数据
DELETE FROM tb_name where condition [order by][limit ];
TRUNCATE tb_name 清空表，并重置计数器(auto_increment)
UPDATE tb_name SET col1=…,col2=… WHERE …

基础表见链接

#插入数据
mysql> insert into tutors set Tname='Tom',Gender='F',Age=30;
Query OK, 1 row affected (0.00 sec)

mysql> select * from tutors;
+-----+--------------+--------+------+
| TID | Tname        | Gender | Age  |
+-----+--------------+--------+------+
|   1 | HongQigong   | M      |   93 |
|   2 | HuangYaoshi  | M      |   63 |
|   3 | Miejueshitai | F      |   72 |
|   4 | OuYangfeng   | M      |   76 |
|   5 | YiDeng       | M      |   90 |
|   6 | YuCanghai    | M      |   56 |
|   7 | Jinlunfawang | M      |   67 |
|   8 | HuYidao      | M      |   42 |
|   9 | NingZhongze  | M      |   49 |
|  10 | Tom          | F      |   30 |
+-----+--------------+--------+------+
10 rows in set (0.00 sec)
#获取最后一条记录
mysql> select * from tutors order by TID desc limit 1;
+-----+-------+--------+------+
| TID | Tname | Gender | Age  |
+-----+-------+--------+------+
|  10 | Tom   | F      |   30 |
+-----+-------+--------+------+
1 row in set (0.00 sec)
#获取最后的索引
mysql> select LAST_INSERT_ID();
+------------------+
| LAST_INSERT_ID() |
+------------------+
|               10 |
+------------------+
1 row in set (0.00 sec)
#将学生表中年龄大于20的学生插入到tutors表中
mysql> select Name,Gender,Age from student where Age >20;
+-------------+--------+------+
| Name        | Gender | Age  |
+-------------+--------+------+
| DingDian    | M      |   25 |
| HuFei       | M      |   31 |
| Xuzhu       | M      |   26 |
| LingHuchong | M      |   22 |
+-------------+--------+------+
4 rows in set (0.00 sec)

mysql> insert into tutors (Tname,Gender,Age) select Name,Gender,Age from student where Age >20;
Query OK, 4 rows affected (0.00 sec)
Records: 4  Duplicates: 0  Warnings: 0

mysql> select * from tutors;
+-----+--------------+--------+------+
| TID | Tname        | Gender | Age  |
+-----+--------------+--------+------+
|   1 | HongQigong   | M      |   93 |
|   2 | HuangYaoshi  | M      |   63 |
|   3 | Miejueshitai | F      |   72 |
|   4 | OuYangfeng   | M      |   76 |
|   5 | YiDeng       | M      |   90 |
|   6 | YuCanghai    | M      |   56 |
|   7 | Jinlunfawang | M      |   67 |
|   8 | HuYidao      | M      |   42 |
|   9 | NingZhongze  | M      |   49 |
|  10 | Tom          | F      |   30 |
|  11 | DingDian     | M      |   25 |
|  12 | HuFei        | M      |   31 |
|  13 | Xuzhu        | M      |   26 |
|  14 | LingHuchong  | M      |   22 |
+-----+--------------+--------+------+
14 rows in set (0.00 sec)