MySQL第四课，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