mysql 学习---->字段
2015-10-15 10:30
369 查看
1.填充字段
mysql> create database test1;
mysql> use test1;
Database changed
mysql> create table t1(id1 int,id2 int(5));
mysql> insert into t1 values(1,1);
mysql> select * from t1;
+------+------+
| id1 | id2 |
+------+------+
| 1 | 1 |
+------+------+
mysql> alter table t1 modify id1 int zerofill;
mysql> alter table t1 modify id2 int(5) zerofill;
mysql> select * from t1;
+------------+-------+
| id1 | id2 |
+------------+-------+
| 0000000001 | 00001 |
+------------+-------+
mysql> insert into t1 values(1,1111111);
mysql> select * from t1;
+------------+---------+
| id1 | id2 |
+------------+---------+
| 0000000001 | 00001 |
| 0000000001 | 1111111 |
+------------+---------+
2.自增长字段的建立
mysql> create table ai1(id int auto_increment not null primary key);
mysql> create table ai2(id int auto_increment not null,primary key(id));
mysql> create table ai3(id int auto_increment not null,unique(id));
3.带小数的字段设置
mysql> alter table t1 rename t1_test;
mysql> desc t1_test;
+-------+---------------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+---------------------------+------+-----+---------+-------+
| id1 | int(10) unsigned zerofill | YES | | NULL | |
| id2 | int(5) unsigned zerofill | YES | | NULL | |
+-------+---------------------------+------+-----+---------+-------+
mysql> create table t1( id1 float(5,2) default null, id2 double(5,2) default null, id3 decimal(5,2) default null);
mysql> insert into t1 values(1.23,1.23,1.23);
mysql> select * from t1;
+------+------+------+
| id1 | id2 | id3 |
+------+------+------+
| 1.23 | 1.23 | 1.23 |
+------+------+------+
mysql> insert into t1 values(1.234,1.234,1.23);
mysql> select * from t1;
+------+------+------+
| id1 | id2 | id3 |
+------+------+------+
| 1.23 | 1.23 | 1.23 |
| 1.23 | 1.23 | 1.23 |
+------+------+------+
mysql> insert into t1 values(1.234,1.234,1.234);
mysql> select * from t1;
+------+------+------+
| id1 | id2 | id3 |
+------+------+------+
| 1.23 | 1.23 | 1.23 |
| 1.23 | 1.23 | 1.23 |
| 1.23 | 1.23 | 1.23 |
+------+------+------+
mysql> show warnings;
mysql> select * from t1;
+------+------+------+
| id1 | id2 | id3 |
+------+------+------+
| 1.23 | 1.23 | 1.23 |
| 1.23 | 1.23 | 1.23 |
| 1.23 | 1.23 | 1.23 |
+------+------+------+
mysql> alter table t1 modify id1 float;
mysql> alter table t1 modify id2 double;
mysql> alter table t1 modify id3 decimal;
mysql> insert into t1 values(1.234,1.234,1.234);
mysql> show warnings;
+-------+------+------------------------------------------+
| Level | Code | Message |
+-------+------+------------------------------------------+
| Note | 1265 | Data truncated for column 'id3' at row 1 |
+-------+------+------------------------------------------+
mysql> select * from t1;
+-------+-------+------+
| id1 | id2 | id3 |
+-------+-------+------+
| 1.23 | 1.23 | 1 |
| 1.23 | 1.23 | 1 |
| 1.23 | 1.23 | 1 |
| 1.234 | 1.234 | 1 |
+-------+-------+------+
mysql> create table t2(id bit(1));
mysql> desc t2;
+-------+--------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+--------+------+-----+---------+-------+
| id | bit(1) | YES | | NULL | |
+-------+--------+------+-----+---------+-------+
mysql> insert into t2 values(1);
mysql> select bin(id),hex(id) from t2;
+---------+---------+
| bin(id) | hex(id) |
+---------+---------+
| 1 | 1 |
+---------+---------+
mysql> insert into t2 values(2);
mysql> show warnings;
+---------+------+---------------------------------------------+
| Level | Code | Message |
+---------+------+---------------------------------------------+
| Warning | 1264 | Out of range value for column 'id' at row 1 |
+---------+------+---------------------------------------------+
mysql> alter table t2 modify id bit(2);
mysql> insert into t2 values(2);
mysql> select bin(id),hex(id) from t2;
+---------+---------+
| bin(id) | hex(id) |
+---------+---------+
| 1 | 1 |
| 1 | 1 |
| 10 | 2 |
+---------+---------+
mysql> create table t(d date,t time ,dt datetime);
mysql> desc t;
+-------+----------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+----------+------+-----+---------+-------+
| d | date | YES | | NULL | |
| t | time | YES | | NULL | |
| dt | datetime | YES | | NULL | |
+-------+----------+------+-----+---------+-------+
4.与时间有关的字段设置
mysql> insert into t values(now(),now(),now());
mysql> select * from t;
+------------+----------+---------------------+
| d | t | dt |
+------------+----------+---------------------+
| 2015-10-02 | 06:04:42 | 2015-10-02 06:04:42 |
+------------+----------+---------------------+
mysql> alter table t rename t_test;
mysql> create table t(id1 timestamp);
mysql> desc t;
+-------+-----------+------+-----+-------------------+-----------------------------+
| Field | Type | Null | Key | Default | Extra |
+-------+-----------+------+-----+-------------------+-----------------------------+
| id1 | timestamp | NO | | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
+-------+-----------+------+-----+-------------------+-----------------------------+
mysql> insert into t values(null);
mysql> select * from t;
+---------------------+
| id1 |
+---------------------+
| 2015-10-02 06:05:20 |
+---------------------+
mysql> alter table t add id2 timestamp;
mysql> show create table t \G;
*************************** 1. row ***************************
Table: t
Create Table: CREATE TABLE `t` (
`id1` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
`id2` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00'
) ENGINE=InnoDB DEFAULT CHARSET=utf8
1 row in set (0.00 sec)
ERROR:
No query specified
mysql> create table t8( id1 timestamp not null default current_timestamp, id2 datetime default null );
mysql> show variables like 'time_zone';
+---------------+--------+
| Variable_name | Value |
+---------------+--------+
| time_zone | SYSTEM |
+---------------+--------+
mysql> select * from t8 ;
mysql> insert into t8 values(now(),now());
mysql> select * from t8;
+---------------------+---------------------+
| id1 | id2 |
+---------------------+---------------------+
| 2015-10-02 06:07:16 | 2015-10-02 06:07:16 |
+---------------------+---------------------+
mysql> set time_zone='+9:00';
mysql> select * from t8;
+---------------------+---------------------+
| id1 | id2 |
+---------------------+---------------------+
| 2015-10-02 22:07:16 | 2015-10-02 06:07:16 |
+---------------------+---------------------+
mysql> desc t8;
+-------+-----------+------+-----+-------------------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+-----------+------+-----+-------------------+-------+
| id1 | timestamp | NO | | CURRENT_TIMESTAMP | |
| id2 | datetime | YES | | NULL | |
+-------+-----------+------+-----+-------------------+-------+
mysql> desc t;
+-------+-----------+------+-----+---------------------+-----------------------------+
| Field | Type | Null | Key | Default | Extra |
+-------+-----------+------+-----+---------------------+-----------------------------+
| id1 | timestamp | NO | | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
| id2 | timestamp | NO | | 0000-00-00 00:00:00 | |
+-------+-----------+------+-----+---------------------+-----------------------------+
mysql> insert into t(id1) values('19700101080001');
mysql> select * from t;
+---------------------+---------------------+
| id1 | id2 |
+---------------------+---------------------+
| 2015-10-02 22:05:20 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
+---------------------+---------------------+
mysql> insert into t(id1) values(19700101080001);
mysql> select * from t;
+---------------------+---------------------+
| id1 | id2 |
+---------------------+---------------------+
| 2015-10-02 22:05:20 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
+---------------------+---------------------+
mysql> insert into t(id1) values(19700101080000);
mysql> select * from t;
+---------------------+---------------------+
| id1 | id2 |
+---------------------+---------------------+
| 2015-10-02 22:05:20 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
+---------------------+---------------------+
4 rows in set (0.00 sec)
mysql> show warnings;
Empty set (0.00 sec)
mysql> desc t1;
+-------+---------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+---------------+------+-----+---------+-------+
| id1 | float | YES | | NULL | |
| id2 | double | YES | | NULL | |
| id3 | decimal(10,0) | YES | | NULL | |
+-------+---------------+------+-----+---------+-------+
3 rows in set (0.01 sec)
mysql> desc t;
+-------+-----------+------+-----+---------------------+-----------------------------+
| Field | Type | Null | Key | Default | Extra |
+-------+-----------+------+-----+---------------------+-----------------------------+
| id1 | timestamp | NO | | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
| id2 | timestamp | NO | | 0000-00-00 00:00:00 | |
+-------+-----------+------+-----+---------------------+-----------------------------+
2 rows in set (0.00 sec)
mysql> insert into t(id1) value('2038-01-19 11:14:07');
mysql> select * from t;
+---------------------+---------------------+
| id1 | id2 |
+---------------------+---------------------+
| 2015-10-02 22:05:20 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 2038-01-19 11:14:07 | 0000-00-00 00:00:00 |
+---------------------+---------------------+
mysql> insert into t(id1) value('2038-01-19 11:14:08');
mysql> select * from t;
+---------------------+---------------------+
| id1 | id2 |
+---------------------+---------------------+
| 2015-10-02 22:05:20 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 2038-01-19 11:14:07 | 0000-00-00 00:00:00 |
| 2038-01-19 11:14:08 | 0000-00-00 00:00:00 |
+---------------------+---------------------+
mysql> insert into t(id1) value('2097-01-19 11:14:08');
mysql> select * from t;
+---------------------+---------------------+
| id1 | id2 |
+---------------------+---------------------+
| 2015-10-02 22:05:20 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 2038-01-19 11:14:07 | 0000-00-00 00:00:00 |
| 2038-01-19 11:14:08 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
+---------------------+---------------------+
mysql> alter table t rename t_date;
mysql> create table t(y year);
mysql> desc t;
+-------+---------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+---------+------+-----+---------+-------+
| y | year(4) | YES | | NULL | |
+-------+---------+------+-----+---------+-------+
mysql> insert into t values(2100);
mysql> select * from t;
+------+
| y |
+------+
| 2100 |
+------+
mysql> create table t6(dt datetime);
mysql> insert into t6 values('2007-9-3 12:10:10');
mysql> insert into t6 values('2007/9/3 12+10+10');
mysql> insert into t6 values('20070903121010');
mysql> insert into t6 values(20070903121010);
mysql> select * from t6;
+---------------------+
| dt |
+---------------------+
| 2007-09-03 12:10:10 |
| 2007-09-03 12:10:10 |
| 2007-09-03 12:10:10 |
| 2007-09-03 12:10:10 |
+---------------------+
5.varchar与char字段的长度
mysql> create table vc(v varchar(4),c char(4));
mysql> insert into vc values('ab ','ab ');
mysql> select length(v),length(c) from vc;
+-----------+-----------+
| length(v) | length(c) |
+-----------+-----------+
| 3 | 2 |
+-----------+-----------+
mysql> select concat(v,'+'),concat(c,'+') from vc;
+---------------+---------------+
| concat(v,'+') | concat(c,'+') |
+---------------+---------------+
| ab + | ab+ |
+---------------+---------------+
mysql> drop table t;
mysql> create table t (c binary(3));
Query OK, 0 rows affected (0.02 sec)
mysql> insert into t set c='a';
Query OK, 1 row affected (0.01 sec)
mysql> select *,hex(c),c='a',c='a\0',c='a\0\0' from t;
+------+--------+-------+---------+-----------+
| c | hex(c) | c='a' | c='a\0' | c='a\0\0' |
+------+--------+-------+---------+-----------+
| a | 610000 | 0 | 0 | 1 |
+------+--------+-------+---------+-----------+
mysql> alter table t rename t_binary;
6.枚举型字段
mysql> create table t(gender enum('M','F'));
mysql> insert into t values('m'),('1'),('f'),(null);
mysql> select * from t;
+--------+
| gender |
+--------+
| M |
| M |
| F |
| NULL |
+--------+
mysql> alter table t rename t_enum;
7.set类型字段设置
mysql> create table t(col set ('a','b','c','d' ));
mysql> insert into t value('a,b'),('a,d,a'),('a,b'),('a,c'),('a');
mysql> select * from t;
+------+
| col |
+------+
| a,b |
| a,d |
| a,b |
| a,c |
| a |
+------+
mysql> create database test1;
mysql> use test1;
Database changed
mysql> create table t1(id1 int,id2 int(5));
mysql> insert into t1 values(1,1);
mysql> select * from t1;
+------+------+
| id1 | id2 |
+------+------+
| 1 | 1 |
+------+------+
mysql> alter table t1 modify id1 int zerofill;
mysql> alter table t1 modify id2 int(5) zerofill;
mysql> select * from t1;
+------------+-------+
| id1 | id2 |
+------------+-------+
| 0000000001 | 00001 |
+------------+-------+
mysql> insert into t1 values(1,1111111);
mysql> select * from t1;
+------------+---------+
| id1 | id2 |
+------------+---------+
| 0000000001 | 00001 |
| 0000000001 | 1111111 |
+------------+---------+
2.自增长字段的建立
mysql> create table ai1(id int auto_increment not null primary key);
mysql> create table ai2(id int auto_increment not null,primary key(id));
mysql> create table ai3(id int auto_increment not null,unique(id));
3.带小数的字段设置
mysql> alter table t1 rename t1_test;
mysql> desc t1_test;
+-------+---------------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+---------------------------+------+-----+---------+-------+
| id1 | int(10) unsigned zerofill | YES | | NULL | |
| id2 | int(5) unsigned zerofill | YES | | NULL | |
+-------+---------------------------+------+-----+---------+-------+
mysql> create table t1( id1 float(5,2) default null, id2 double(5,2) default null, id3 decimal(5,2) default null);
mysql> insert into t1 values(1.23,1.23,1.23);
mysql> select * from t1;
+------+------+------+
| id1 | id2 | id3 |
+------+------+------+
| 1.23 | 1.23 | 1.23 |
+------+------+------+
mysql> insert into t1 values(1.234,1.234,1.23);
mysql> select * from t1;
+------+------+------+
| id1 | id2 | id3 |
+------+------+------+
| 1.23 | 1.23 | 1.23 |
| 1.23 | 1.23 | 1.23 |
+------+------+------+
mysql> insert into t1 values(1.234,1.234,1.234);
mysql> select * from t1;
+------+------+------+
| id1 | id2 | id3 |
+------+------+------+
| 1.23 | 1.23 | 1.23 |
| 1.23 | 1.23 | 1.23 |
| 1.23 | 1.23 | 1.23 |
+------+------+------+
mysql> show warnings;
mysql> select * from t1;
+------+------+------+
| id1 | id2 | id3 |
+------+------+------+
| 1.23 | 1.23 | 1.23 |
| 1.23 | 1.23 | 1.23 |
| 1.23 | 1.23 | 1.23 |
+------+------+------+
mysql> alter table t1 modify id1 float;
mysql> alter table t1 modify id2 double;
mysql> alter table t1 modify id3 decimal;
mysql> insert into t1 values(1.234,1.234,1.234);
mysql> show warnings;
+-------+------+------------------------------------------+
| Level | Code | Message |
+-------+------+------------------------------------------+
| Note | 1265 | Data truncated for column 'id3' at row 1 |
+-------+------+------------------------------------------+
mysql> select * from t1;
+-------+-------+------+
| id1 | id2 | id3 |
+-------+-------+------+
| 1.23 | 1.23 | 1 |
| 1.23 | 1.23 | 1 |
| 1.23 | 1.23 | 1 |
| 1.234 | 1.234 | 1 |
+-------+-------+------+
mysql> create table t2(id bit(1));
mysql> desc t2;
+-------+--------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+--------+------+-----+---------+-------+
| id | bit(1) | YES | | NULL | |
+-------+--------+------+-----+---------+-------+
mysql> insert into t2 values(1);
mysql> select bin(id),hex(id) from t2;
+---------+---------+
| bin(id) | hex(id) |
+---------+---------+
| 1 | 1 |
+---------+---------+
mysql> insert into t2 values(2);
mysql> show warnings;
+---------+------+---------------------------------------------+
| Level | Code | Message |
+---------+------+---------------------------------------------+
| Warning | 1264 | Out of range value for column 'id' at row 1 |
+---------+------+---------------------------------------------+
mysql> alter table t2 modify id bit(2);
mysql> insert into t2 values(2);
mysql> select bin(id),hex(id) from t2;
+---------+---------+
| bin(id) | hex(id) |
+---------+---------+
| 1 | 1 |
| 1 | 1 |
| 10 | 2 |
+---------+---------+
mysql> create table t(d date,t time ,dt datetime);
mysql> desc t;
+-------+----------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+----------+------+-----+---------+-------+
| d | date | YES | | NULL | |
| t | time | YES | | NULL | |
| dt | datetime | YES | | NULL | |
+-------+----------+------+-----+---------+-------+
4.与时间有关的字段设置
mysql> insert into t values(now(),now(),now());
mysql> select * from t;
+------------+----------+---------------------+
| d | t | dt |
+------------+----------+---------------------+
| 2015-10-02 | 06:04:42 | 2015-10-02 06:04:42 |
+------------+----------+---------------------+
mysql> alter table t rename t_test;
mysql> create table t(id1 timestamp);
mysql> desc t;
+-------+-----------+------+-----+-------------------+-----------------------------+
| Field | Type | Null | Key | Default | Extra |
+-------+-----------+------+-----+-------------------+-----------------------------+
| id1 | timestamp | NO | | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
+-------+-----------+------+-----+-------------------+-----------------------------+
mysql> insert into t values(null);
mysql> select * from t;
+---------------------+
| id1 |
+---------------------+
| 2015-10-02 06:05:20 |
+---------------------+
mysql> alter table t add id2 timestamp;
mysql> show create table t \G;
*************************** 1. row ***************************
Table: t
Create Table: CREATE TABLE `t` (
`id1` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
`id2` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00'
) ENGINE=InnoDB DEFAULT CHARSET=utf8
1 row in set (0.00 sec)
ERROR:
No query specified
mysql> create table t8( id1 timestamp not null default current_timestamp, id2 datetime default null );
mysql> show variables like 'time_zone';
+---------------+--------+
| Variable_name | Value |
+---------------+--------+
| time_zone | SYSTEM |
+---------------+--------+
mysql> select * from t8 ;
mysql> insert into t8 values(now(),now());
mysql> select * from t8;
+---------------------+---------------------+
| id1 | id2 |
+---------------------+---------------------+
| 2015-10-02 06:07:16 | 2015-10-02 06:07:16 |
+---------------------+---------------------+
mysql> set time_zone='+9:00';
mysql> select * from t8;
+---------------------+---------------------+
| id1 | id2 |
+---------------------+---------------------+
| 2015-10-02 22:07:16 | 2015-10-02 06:07:16 |
+---------------------+---------------------+
mysql> desc t8;
+-------+-----------+------+-----+-------------------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+-----------+------+-----+-------------------+-------+
| id1 | timestamp | NO | | CURRENT_TIMESTAMP | |
| id2 | datetime | YES | | NULL | |
+-------+-----------+------+-----+-------------------+-------+
mysql> desc t;
+-------+-----------+------+-----+---------------------+-----------------------------+
| Field | Type | Null | Key | Default | Extra |
+-------+-----------+------+-----+---------------------+-----------------------------+
| id1 | timestamp | NO | | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
| id2 | timestamp | NO | | 0000-00-00 00:00:00 | |
+-------+-----------+------+-----+---------------------+-----------------------------+
mysql> insert into t(id1) values('19700101080001');
mysql> select * from t;
+---------------------+---------------------+
| id1 | id2 |
+---------------------+---------------------+
| 2015-10-02 22:05:20 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
+---------------------+---------------------+
mysql> insert into t(id1) values(19700101080001);
mysql> select * from t;
+---------------------+---------------------+
| id1 | id2 |
+---------------------+---------------------+
| 2015-10-02 22:05:20 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
+---------------------+---------------------+
mysql> insert into t(id1) values(19700101080000);
mysql> select * from t;
+---------------------+---------------------+
| id1 | id2 |
+---------------------+---------------------+
| 2015-10-02 22:05:20 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
+---------------------+---------------------+
4 rows in set (0.00 sec)
mysql> show warnings;
Empty set (0.00 sec)
mysql> desc t1;
+-------+---------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+---------------+------+-----+---------+-------+
| id1 | float | YES | | NULL | |
| id2 | double | YES | | NULL | |
| id3 | decimal(10,0) | YES | | NULL | |
+-------+---------------+------+-----+---------+-------+
3 rows in set (0.01 sec)
mysql> desc t;
+-------+-----------+------+-----+---------------------+-----------------------------+
| Field | Type | Null | Key | Default | Extra |
+-------+-----------+------+-----+---------------------+-----------------------------+
| id1 | timestamp | NO | | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
| id2 | timestamp | NO | | 0000-00-00 00:00:00 | |
+-------+-----------+------+-----+---------------------+-----------------------------+
2 rows in set (0.00 sec)
mysql> insert into t(id1) value('2038-01-19 11:14:07');
mysql> select * from t;
+---------------------+---------------------+
| id1 | id2 |
+---------------------+---------------------+
| 2015-10-02 22:05:20 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 2038-01-19 11:14:07 | 0000-00-00 00:00:00 |
+---------------------+---------------------+
mysql> insert into t(id1) value('2038-01-19 11:14:08');
mysql> select * from t;
+---------------------+---------------------+
| id1 | id2 |
+---------------------+---------------------+
| 2015-10-02 22:05:20 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 2038-01-19 11:14:07 | 0000-00-00 00:00:00 |
| 2038-01-19 11:14:08 | 0000-00-00 00:00:00 |
+---------------------+---------------------+
mysql> insert into t(id1) value('2097-01-19 11:14:08');
mysql> select * from t;
+---------------------+---------------------+
| id1 | id2 |
+---------------------+---------------------+
| 2015-10-02 22:05:20 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
| 2038-01-19 11:14:07 | 0000-00-00 00:00:00 |
| 2038-01-19 11:14:08 | 0000-00-00 00:00:00 |
| 0000-00-00 00:00:00 | 0000-00-00 00:00:00 |
+---------------------+---------------------+
mysql> alter table t rename t_date;
mysql> create table t(y year);
mysql> desc t;
+-------+---------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+---------+------+-----+---------+-------+
| y | year(4) | YES | | NULL | |
+-------+---------+------+-----+---------+-------+
mysql> insert into t values(2100);
mysql> select * from t;
+------+
| y |
+------+
| 2100 |
+------+
mysql> create table t6(dt datetime);
mysql> insert into t6 values('2007-9-3 12:10:10');
mysql> insert into t6 values('2007/9/3 12+10+10');
mysql> insert into t6 values('20070903121010');
mysql> insert into t6 values(20070903121010);
mysql> select * from t6;
+---------------------+
| dt |
+---------------------+
| 2007-09-03 12:10:10 |
| 2007-09-03 12:10:10 |
| 2007-09-03 12:10:10 |
| 2007-09-03 12:10:10 |
+---------------------+
5.varchar与char字段的长度
mysql> create table vc(v varchar(4),c char(4));
mysql> insert into vc values('ab ','ab ');
mysql> select length(v),length(c) from vc;
+-----------+-----------+
| length(v) | length(c) |
+-----------+-----------+
| 3 | 2 |
+-----------+-----------+
mysql> select concat(v,'+'),concat(c,'+') from vc;
+---------------+---------------+
| concat(v,'+') | concat(c,'+') |
+---------------+---------------+
| ab + | ab+ |
+---------------+---------------+
mysql> drop table t;
mysql> create table t (c binary(3));
Query OK, 0 rows affected (0.02 sec)
mysql> insert into t set c='a';
Query OK, 1 row affected (0.01 sec)
mysql> select *,hex(c),c='a',c='a\0',c='a\0\0' from t;
+------+--------+-------+---------+-----------+
| c | hex(c) | c='a' | c='a\0' | c='a\0\0' |
+------+--------+-------+---------+-----------+
| a | 610000 | 0 | 0 | 1 |
+------+--------+-------+---------+-----------+
mysql> alter table t rename t_binary;
6.枚举型字段
mysql> create table t(gender enum('M','F'));
mysql> insert into t values('m'),('1'),('f'),(null);
mysql> select * from t;
+--------+
| gender |
+--------+
| M |
| M |
| F |
| NULL |
+--------+
mysql> alter table t rename t_enum;
7.set类型字段设置
mysql> create table t(col set ('a','b','c','d' ));
mysql> insert into t value('a,b'),('a,d,a'),('a,b'),('a,c'),('a');
mysql> select * from t;
+------+
| col |
+------+
| a,b |
| a,d |
| a,b |
| a,c |
| a |
+------+
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