MySQL第四课

create table biao(
    name varchar(20) primary key,
    age int(11) not null,
    sex char(11)default 1,
    love varchar(11)
    );
query ok, 0 rows affected

此时name设置了主键约束，age设置了非空约束，sex默认值为一

查看： desc biao;
+-------+-------------+------+-----+---------+-------+
| field | type        | null | key | default | extra |
+-------+-------------+------+-----+---------+-------+
| name  | varchar(20) | no   | pri | null    |       |
| age   | int(11)     | no   |     | null    |       |
| sex   | char(11)    | yes  |     | 1       |       |
| love  | varchar(11) | yes  |     | null    |       |
+-------+-------------+------+-----+---------+-------+
4 rows in set

添加数据：

1.

insert into biao (name,age,sex,love) values ('张三',41,'男','e');
query ok, 1 row affected

查看：select*from biao;
+------+-----+-----+------+
| name | age | sex | love |
+------+-----+-----+------+
| 张三 |  41 | 男  | e    |
+------+-----+-----+------+
1 row in set

2.

insert into biao  values ('张',40,'男','em');
query ok, 1 row affected

select*from biao;
+------+-----+-----+------+
| name | age | sex | love |
+------+-----+-----+------+
| 张三 |  41 | 男  | e    |
| 张   |  40 | 男  | em   |
+------+-----+-----+------+
2 rows in set

3.

 insert into biao (sex) values ('男');
query ok, 1 row affected

select*from biao;
+------+-----+-----+------+
| name | age | sex | love |
+------+-----+-----+------+
| 张三 |  41 | 男  | e    |
| 张   |  40 | 男  | em   |
|      |   0 | 男  | null |
+------+-----+-----+------+
3 rows in set

4.

insert into biao(name,age,sex,love) values('李四',39,'女','ex'),('王五',38,'男','van'),('甲',20,'男','emm');
query ok, 3 rows affected
records: 3  duplicates: 0  warnings: 0

select*from biao;
+------+-----+-----+------+
| name | age | sex | love |
+------+-----+-----+------+
| 张三 |  41 | 男  | e    |
| 张   |  40 | 男  | em   |
|      |   0 | 男  | null |
| 李四 |  39 | 女  | ex   |
| 王五 |  38 | 男  | van  |
| 甲   |  20 | 男  | emm  |
+------+-----+-----+------+
6 rows in set