mysql数据5.6.0和5.1.7的null字段索引测试

如果保函null字段是数字 is null 和is not null都不走索引

如果保函null字段是字符 is null不走索引 和is not null会走索引

字符类型可以默认‘‘ 数字类型可以默认0

1、数据库为5.6.0版本测试

mysql> select @@version;

+------------+

| @@version  |

+------------+

| 5.6.10-log |

+------------+

1 row in set (0.00 sec)

mysql>

mysql>  create table test_innodb (id int(11) unsigned NOT NULL primary key AUTO_INCREMENT,name varchar(100)) engine=innodb;

Query OK, 0 rows affected (0.16 sec)

mysql> show create table test_innodb\G

*************************** 1. row ***************************

Table: test_innodb

Create Table: CREATE TABLE `test_innodb` (

`id` int(11) unsigned NOT NULL AUTO_INCREMENT,

`name` varchar(100) DEFAULT NULL,

PRIMARY KEY (`id`)

) ENGINE=InnoDB DEFAULT CHARSET=utf8

1 row in set (0.00 sec)

mysql> insert into test_innodb(name) values(‘hlf‘),(‘huanglf‘);

Query OK, 2 rows affected (0.00 sec)

Records: 2  Duplicates: 0  Warnings: 0

mysql> show create table test_innodb\G

*************************** 1. row ***************************

Table: test_innodb

Create Table: CREATE TABLE `test_innodb` (

`id` int(11) unsigned NOT NULL AUTO_INCREMENT,

`name` varchar(100) DEFAULT NULL,

PRIMARY KEY (`id`)

) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8

1 row in set (0.00 sec)

mysql> optimize table test_innodb;

+------------------+----------+----------+-------------------------------------------------------------------+

| Table            | Op       | Msg_type | Msg_text                                                          |

+------------------+----------+----------+-------------------------------------------------------------------+

| test.test_innodb | optimize | note     | Table does not support optimize, doing recreate + analyze instead |

| test.test_innodb | optimize | status   | OK                                                                |

+------------------+----------+----------+-------------------------------------------------------------------+

2 rows in set (0.30 sec)

mysql> show create table test_innodb\G

*************************** 1. row ***************************

Table: test_innodb

Create Table: CREATE TABLE `test_innodb` (

`id` int(11) unsigned NOT NULL AUTO_INCREMENT,

`name` varchar(100) DEFAULT NULL,

PRIMARY KEY (`id`)

) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8

1 row in set (0.00 sec)

mysql>

#####################################

增加列并测试null字段索引

mysql> alter table test_INNODB ADD COLUMN numb int(8) default null;

Query OK, 0 rows affected (0.55 sec)

Records: 0  Duplicates: 0  Warnings: 0

mysql>

mysql>

mysql> alter table test_INNODB drop COLUMN numb ;

Query OK, 0 rows affected (0.55 sec)

Records: 0  Duplicates: 0  Warnings: 0

mysql> show create table test_innodb;

+-------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

| Table       | Create Table                                                                                                                                                                                 |

+-------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

| test_innodb | CREATE TABLE `test_innodb` (

`id` int(11) unsigned NOT NULL AUTO_INCREMENT,

`name` varchar(100) DEFAULT NULL,

PRIMARY KEY (`id`)

) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8 |

+-------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

1 row in set (0.00 sec)

mysql> alter table test_INNODB ADD COLUMN numb int(8) default null,add column addr varchar(100) default null;

Query OK, 0 rows affected (0.55 sec)

Records: 0  Duplicates: 0  Warnings: 0

mysql> show create table test_innodb;

+-------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

| Table       | Create Table                                                                                                                                                                                                                                                   |

+-------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

| test_innodb | CREATE TABLE `test_innodb` (

`id` int(11) unsigned NOT NULL AUTO_INCREMENT,

`name` varchar(100) DEFAULT NULL,

`numb` int(8) DEFAULT NULL,

`addr` varchar(100) DEFAULT NULL,

PRIMARY KEY (`id`)

) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8 |

+-------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

1 row in set (0.00 sec)

mysql>

mysql> alter table test_innodb add index idx_numb(numb);

Query OK, 0 rows affected (0.02 sec)

Records: 0  Duplicates: 0  Warnings: 0

mysql>

mysql> alter table test_innodb add index idx_addr(addr);

Query OK, 0 rows affected (0.01 sec)

Records: 0  Duplicates: 0  Warnings: 0

mysql> show create table test_innodb;

+-------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

| Table       | Create Table                                                                                                                                                                                                                                                                                                         |

+-------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

| test_innodb | CREATE TABLE `test_innodb` (

`id` int(11) unsigned NOT NULL AUTO_INCREMENT,

`name` varchar(100) DEFAULT NULL,

`numb` int(8) DEFAULT NULL,

`addr` varchar(100) DEFAULT NULL,

PRIMARY KEY (`id`),

KEY `idx_numb` (`numb`),

KEY `idx_addr` (`addr`)

) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8 |

+-------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

1 row in set (0.00 sec)

mysql>

mysql> insert into test_innodb(name,numb,addr) values(‘huanglingfei‘,80,‘chengdu‘),(‘wanger‘),(‘mazhi‘,‘guizhou‘),(‘zhangsan‘,60);

ERROR 1136 (21S01): Column count doesn‘t match value count at row 2

mysql>

mysql> insert into test_innodb(name,numb,addr) values(‘huanglingfei‘,80,‘chengdu‘);

Query OK, 1 row affected (0.00 sec)

mysql>

mysql>

mysql>

mysql>

mysql> insert into test_innodb(name) values(‘wanger‘);

Query OK, 1 row affected (0.00 sec)

mysql>

插入错误类型是出现警告并把插字符串自动替换为数字0

mysql> insert into test_innodb(name,numb) values(‘mazhi‘,‘guizhou‘),(‘zhangsan‘,60);

Query OK, 2 rows affected, 1 warning (0.00 sec)

Records: 2  Duplicates: 0  Warnings: 1

mysql> select * from test_innodb;

+----+--------------+------+---------+

| id | name         | numb | addr    |

+----+--------------+------+---------+

|  1 | hlf          | NULL | NULL    |

|  2 | huanglf      | NULL | NULL    |

|  3 | huanglingfei |   80 | chengdu |

|  4 | wanger       | NULL | NULL    |

|  5 | mazhi        |    0 | NULL    |

|  6 | zhangsan     |   60 | NULL    |

+----+--------------+------+---------+

6 rows in set (0.00 sec)

mysql>

mysql> explain select * from test_innodb where id in(3,4,5);

+----+-------------+-------------+-------+---------------+---------+---------+------+------+-------------+

| id | select_type | table       | type  | possible_keys | key     | key_len | ref  | rows | Extra       |

+----+-------------+-------------+-------+---------------+---------+---------+------+------+-------------+

|  1 | SIMPLE      | test_innodb | range | PRIMARY       | PRIMARY | 4       | NULL |    3 | Using where |

+----+-------------+-------------+-------+---------------+---------+---------+------+------+-------------+

1 row in set (0.00 sec)

mysql> select * from test_innodb where id in(3,4,5);

+----+--------------+------+---------+

| id | name         | numb | addr    |

+----+--------------+------+---------+

|  3 | huanglingfei |   80 | chengdu |

|  4 | wanger       | NULL | NULL    |

|  5 | mazhi        |    0 | NULL    |

+----+--------------+------+---------+

3 rows in set (0.00 sec)

mysql>

数字字段

mysql>

mysql> explain select * from test_innodb where numb=80;

+----+-------------+-------------+------+---------------+----------+---------+-------+------+-------+

| id | select_type | table       | type | possible_keys | key      | key_len | ref   | rows | Extra |

+----+-------------+-------------+------+---------------+----------+---------+-------+------+-------+

|  1 | SIMPLE      | test_innodb | ref  | idx_numb      | idx_numb | 5       | const |    1 | NULL  |

+----+-------------+-------------+------+---------------+----------+---------+-------+------+-------+

1 row in set (0.00 sec)

mysql>

mysql> explain select * from test_innodb where numb is not null;

+----+-------------+-------------+------+---------------+------+---------+------+------+-------------+

| id | select_type | table       | type | possible_keys | key  | key_len | ref  | rows | Extra       |

+----+-------------+-------------+------+---------------+------+---------+------+------+-------------+

|  1 | SIMPLE      | test_innodb | ALL  | idx_numb      | NULL | NULL    | NULL |    6 | Using where |

+----+-------------+-------------+------+---------------+------+---------+------+------+-------------+

1 row in set (0.00 sec)

mysql>

mysql>

mysql> select * from test_innodb where numb is not null;

+----+--------------+------+---------+

| id | name         | numb | addr    |

+----+--------------+------+---------+

|  3 | huanglingfei |   80 | chengdu |

|  5 | mazhi        |    0 | NULL    |

|  6 | zhangsan     |   60 | NULL    |

+----+--------------+------+---------+

3 rows in set (0.00 sec)

mysql>

mysql> explain select * from test_innodb where numb is null;

+----+-------------+-------------+------+---------------+------+---------+------+------+-------------+

| id | select_type | table       | type | possible_keys | key  | key_len | ref  | rows | Extra       |

+----+-------------+-------------+------+---------------+------+---------+------+------+-------------+

|  1 | SIMPLE      | test_innodb | ALL  | idx_numb      | NULL | NULL    | NULL |    6 | Using where |

+----+-------------+-------------+------+---------------+------+---------+------+------+-------------+

1 row in set (0.00 sec)

mysql>

mysql> select * from test_innodb where numb is null;

+----+---------+------+------+

| id | name    | numb | addr |

+----+---------+------+------+

|  1 | hlf     | NULL | NULL |

|  2 | huanglf | NULL | NULL |

|  4 | wanger  | NULL | NULL |

+----+---------+------+------+

3 rows in set (0.00 sec)

mysql>

字符字段 is not null 居然走了索引

mysql> explain select * from test_innodb where  addr=‘chengdu‘;

+----+-------------+-------------+------+---------------+----------+---------+-------+------+-----------------------+

| id | select_type | table       | type | possible_keys | key      | key_len | ref   | rows | Extra                 |

+----+-------------+-------------+------+---------------+----------+---------+-------+------+-----------------------+

|  1 | SIMPLE      | test_innodb | ref  | idx_addr      | idx_addr | 303     | const |    1 | Using index condition |

+----+-------------+-------------+------+---------------+----------+---------+-------+------+-----------------------+

1 row in set (0.00 sec)

mysql>

mysql> select * from test_innodb where  addr=‘chengdu‘;

+----+--------------+------+---------+

| id | name         | numb | addr    |

+----+--------------+------+---------+

|  3 | huanglingfei |   80 | chengdu |

+----+--------------+------+---------+

1 row in set (0.00 sec)

mysql>

mysql> explain select * from test_innodb where  addr is null;

+----+-------------+-------------+------+---------------+------+---------+------+------+-------------+

| id | select_type | table       | type | possible_keys | key  | key_len | ref  | rows | Extra       |

+----+-------------+-------------+------+---------------+------+---------+------+------+-------------+

|  1 | SIMPLE      | test_innodb | ALL  | idx_addr      | NULL | NULL    | NULL |    6 | Using where |

+----+-------------+-------------+------+---------------+------+---------+------+------+-------------+

1 row in set (0.00 sec)

mysql>

mysql>

mysql>

mysql> select * from test_innodb where  addr is null;

+----+----------+------+------+

| id | name     | numb | addr |

+----+----------+------+------+

|  1 | hlf      | NULL | NULL |

|  2 | huanglf  | NULL | NULL |

|  4 | wanger   | NULL | NULL |

|  5 | mazhi    |    0 | NULL |

|  6 | zhangsan |   60 | NULL |

+----+----------+------+------+

5 rows in set (0.00 sec)

mysql>

mysql> explain select * from test_innodb where  addr is not null;

+----+-------------+-------------+-------+---------------+----------+---------+------+------+-----------------------+

| id | select_type | table       | type  | possible_keys | key      | key_len | ref  | rows | Extra                 |

+----+-------------+-------------+-------+---------------+----------+---------+------+------+-----------------------+

|  1 | SIMPLE      | test_innodb | range | idx_addr      | idx_addr | 303     | NULL |    1 | Using index condition |

+----+-------------+-------------+-------+---------------+----------+---------+------+------+-----------------------+

1 row in set (0.00 sec)

mysql>

mysql>

mysql> select * from test_innodb where  addr is not null;

+----+--------------+------+---------+

| id | name         | numb | addr    |

+----+--------------+------+---------+

|  3 | huanglingfei |   80 | chengdu |

+----+--------------+------+---------+

1 row in set (0.00 sec)

mysql>

2、数据库为5.1.7版本测试：

mysql> select @@version;

+------------+

| @@version  |

+------------+

| 5.1.73-log |

+------------+

1 row in set (0.00 sec)

mysql>

create table test_innodb (id int(11) unsigned NOT NULL primary key AUTO_INCREMENT,

name varchar(100),

numb int(8) default null,

addr varchar(100) default null,

key idx_numb (numb),

key idx_addr (addr)

) engine=innodb;

mysql> create table test_innodb (id int(11) unsigned NOT NULL primary key AUTO_INCREMENT,

-> name varchar(100),

-> numb int(8) default null,

-> addr varchar(100) default null,

-> key idx_numb (numb),

-> key idx_addr (addr)

-> ) engine=innodb;

Query OK, 0 rows affected (0.25 sec)

mysql>

insert into test_innodb(name) values(‘hlf‘),(‘huanglf‘);

insert into test_innodb(name,numb,addr) values(‘huanglingfei‘,80,‘chengdu‘);

insert into test_innodb(name) values(‘wanger‘);

insert into test_innodb(name,numb) values(‘mazhi‘,‘guizhou‘),(‘zhangsan‘,60);

mysql> insert into test_innodb(name) values(‘hlf‘),(‘huanglf‘);

Query OK, 2 rows affected (0.00 sec)

Records: 2  Duplicates: 0  Warnings: 0

mysql> insert into test_innodb(name,numb,addr) values(‘huanglingfei‘,80,‘chengdu‘);

Query OK, 1 row affected (0.00 sec)

mysql> insert into test_innodb(name) values(‘wanger‘);

Query OK, 1 row affected (0.00 sec)

mysql> insert into test_innodb(name,numb) values(‘mazhi‘,‘guizhou‘),(‘zhangsan‘,60);

ERROR 1366 (HY000): Incorrect integer value: ‘guizhou‘ for column ‘numb‘ at row 1

mysql>

mysql> insert into test_innodb(name,numb) values(‘mazhi‘,‘0‘),(‘zhangsan‘,60);

Query OK, 2 rows affected (0.00 sec)

Records: 2  Duplicates: 0  Warnings: 0

mysql> select * from test_innodb;

+----+--------------+------+---------+

| id | name         | numb | addr    |

+----+--------------+------+---------+

|  1 | hlf          | NULL | NULL    |

|  2 | huanglf      | NULL | NULL    |

|  3 | huanglingfei |   80 | chengdu |

|  4 | wanger       | NULL | NULL    |

|  5 | mazhi        |    0 | NULL    |

|  6 | zhangsan     |   60 | NULL    |

+----+--------------+------+---------+

6 rows in set (0.00 sec)

mysql>

从结果看字符字段is not null 也是会走索引的

mysql> explain select * from test_innodb where numb=80;

+----+-------------+-------------+------+---------------+----------+---------+-------+------+-------------+

| id | select_type | table       | type | possible_keys | key      | key_len | ref   | rows | Extra       |

+----+-------------+-------------+------+---------------+----------+---------+-------+------+-------------+

|  1 | SIMPLE      | test_innodb | ref  | idx_numb      | idx_numb | 5       | const |    1 | Using where |

+----+-------------+-------------+------+---------------+----------+---------+-------+------+-------------+

1 row in set (0.00 sec)

mysql>

mysql> explain select * from test_innodb where numb is null;

+----+-------------+-------------+------+---------------+------+---------+------+------+-------------+

| id | select_type | table       | type | possible_keys | key  | key_len | ref  | rows | Extra       |

+----+-------------+-------------+------+---------------+------+---------+------+------+-------------+

|  1 | SIMPLE      | test_innodb | ALL  | idx_numb      | NULL | NULL    | NULL |    6 | Using where |

+----+-------------+-------------+------+---------------+------+---------+------+------+-------------+

1 row in set (0.00 sec)

mysql> explain select * from test_innodb where numb is not null;

+----+-------------+-------------+------+---------------+------+---------+------+------+-------------+

| id | select_type | table       | type | possible_keys | key  | key_len | ref  | rows | Extra       |

+----+-------------+-------------+------+---------------+------+---------+------+------+-------------+

|  1 | SIMPLE      | test_innodb | ALL  | idx_numb      | NULL | NULL    | NULL |    6 | Using where |

+----+-------------+-------------+------+---------------+------+---------+------+------+-------------+

1 row in set (0.00 sec)

mysql>

mysql> explain select * from test_innodb where addr is null;

+----+-------------+-------------+------+---------------+------+---------+------+------+-------------+

| id | select_type | table       | type | possible_keys | key  | key_len | ref  | rows | Extra       |

+----+-------------+-------------+------+---------------+------+---------+------+------+-------------+

|  1 | SIMPLE      | test_innodb | ALL  | idx_addr      | NULL | NULL    | NULL |    6 | Using where |

+----+-------------+-------------+------+---------------+------+---------+------+------+-------------+

1 row in set (0.00 sec)

mysql>

mysql>

mysql> explain select * from test_innodb where addr is not null;

+----+-------------+-------------+-------+---------------+----------+---------+------+------+-------------+

| id | select_type | table       | type  | possible_keys | key      | key_len | ref  | rows | Extra       |

+----+-------------+-------------+-------+---------------+----------+---------+------+------+-------------+

|  1 | SIMPLE      | test_innodb | range | idx_addr      | idx_addr | 303     | NULL |    1 | Using where |

+----+-------------+-------------+-------+---------------+----------+---------+------+------+-------------+

1 row in set (0.00 sec)

mysql>

时间： 2024-10-05 03:33:27

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