indexing - Mariadb:为什么我的查询没有使用索引？-6ren

indexing - Mariadb:为什么我的查询没有使用索引？

转载作者：行者123 更新时间：2023-12-04 17:45:30

我想弄清楚为什么这个查询没有使用索引(所以它很长)。

explain select count(*) as aggregate 
from `megabase_sms_data_1` 
left join `megabase_sms_thematic_repulse_1` 
    on `megabase_sms_data_1`.`contact_id` = `megabase_sms_thematic_repulse_1`.`megabase_data_id`
where not (megabase_sms_thematic_repulse_1.thematic_id <=> 6) 
    and `age` in ('2', '3', '4', '5', '6', '7', '8', '9', '10', '11', '12', '-1');


+------+-------------+---------------------------------+------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+------------------------------------------------------------+---------+-------------------------------------------+----------+-------------+
| id   | select_type | table                           | type | possible_keys                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | key                                                        | key_len | ref                                       | rows     | Extra       |
+------+-------------+---------------------------------+------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+------------------------------------------------------------+---------+-------------------------------------------+----------+-------------+
|    1 | SIMPLE      | megabase_sms_data_1             | ALL  | tmp_megabase_sms_data_1_age_index,tmp_megabase_sms_data_1_age_incomes_index,tmp_megabase_sms_data_1_age_housing_zipcode_sex_index,tmp_megabase_sms_data_1_age_zipcode_type_sex_index,tmp_megabase_sms_data_1_age_family_zipcode_sex_index,tmp_megabase_sms_data_1_age_couple_zipcode_sex_index,tmp_megabase_sms_data_1_age_department_sex_housing_index,tmp_megabase_sms_data_1_age_type_department_sex_index,tmp_megabase_sms_data_1_age_family_department_sex_index,tmp_megabase_sms_data_1_age_sex_couple_department_index | NULL                                                       | NULL    | NULL                                      | 20508191 | Using where |
|    1 | SIMPLE      | megabase_sms_thematic_repulse_1 | ref  | tmp_megabase_sms_thematic_repulse_1_megabase_data_id_index                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | tmp_megabase_sms_thematic_repulse_1_megabase_data_id_index | 8       | adsconsole.megabase_sms_data_1.contact_id |        1 | Using where |

我试图将索引添加到 contact_id 上的表，但它没有使用它。可能是我误解了一些概念。

我有那两个表:

 DESCRIBE megabase_sms_data_1;
+----------------+------------------+------+-----+---------+----------------+
| Field          | Type             | Null | Key | Default | Extra          |
+----------------+------------------+------+-----+---------+----------------+
| contact_id     | int(10) unsigned | NO   | PRI | NULL    | auto_increment |
| sms_md5        | varchar(255)     | NO   | MUL | NULL    |                |
| sms            | varchar(255)     | NO   | MUL | NULL    |                |
| age            | tinyint(4)       | NO   | MUL | NULL    |                |
| sex            | tinyint(4)       | NO   | MUL | NULL    |                |
| couple         | tinyint(4)       | NO   | MUL | NULL    |                |
| family         | tinyint(4)       | NO   | MUL | NULL    |                |
| type           | tinyint(4)       | NO   | MUL | NULL    |                |
| housing        | tinyint(4)       | NO   | MUL | NULL    |                |
| gather_date    | date             | NO   |     | NULL    |                |
| freshness_date | date             | NO   |     | NULL    |                |
| zipcode        | char(5)          | NO   | MUL | NULL    |                |
| department     | char(2)          | NO   | MUL | NULL    |                |
| address        | varchar(255)     | NO   |     | NULL    |                |
| city           | varchar(255)     | NO   |     | NULL    |                |
| latitude       | double           | NO   |     | NULL    |                |
| longitude      | double           | NO   |     | NULL    |                |
| incomes        | tinyint(4)       | NO   | MUL | NULL    |                |
| csp            | tinyint(4)       | NO   |     | NULL    |                |
| adr_iris       | varchar(255)     | NO   |     | NULL    |                |
| adr_inse       | varchar(255)     | NO   |     | NULL    |                |
+----------------+------------------+------+-----+---------+----------------+
21 rows in set (0.00 sec)


 SHOW INDEX FROM megabase_sms_data_1;
+---------------------+------------+----------------------------------------------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+                         ---------------+
| Table               | Non_unique | Key_name                                                 | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment |                          Index_comment |
+---------------------+------------+----------------------------------------------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+                         ---------------+
| megabase_sms_data_1 |          0 | PRIMARY                                                  |            1 | contact_id  | A         |    20508191 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          0 | tmp_megabase_sms_data_1_contact_id                       |            1 | contact_id  | A         |    20508191 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_sms_md5_index                    |            1 | sms_md5     | A         |    20508191 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_index                        |            1 | age         | A         |          13 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_sex_index                        |            1 | sex         | A         |           3 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_couple_index                     |            1 | couple      | A         |           2 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_family_index                     |            1 | family      | A         |           2 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_type_index                       |            1 | type        | A         |           2 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_housing_index                    |            1 | housing     | A         |           2 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_department_index                 |            1 | department  | A         |          99 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_incomes_index                    |            1 | incomes     | A         |          10 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_zipcode_index                    |            1 | zipcode     | A         |       21497 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_incomes_index                |            1 | age         | A         |          13 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_incomes_index                |            2 | incomes     | A         |         131 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_type_age_index                   |            1 | type        | A         |           2 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_type_age_index                   |            2 | age         | A         |          39 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_couple_age_index                 |            1 | couple      | A         |           2 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_couple_age_index                 |            2 | age         | A         |          39 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_family_age_index                 |            1 | family      | A         |           2 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_family_age_index                 |            2 | age         | A         |          39 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_sex_age_index                    |            1 | sex         | A         |           3 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_sex_age_index                    |            2 | age         | A         |          52 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_incomes_age_index                |            1 | incomes     | A         |          10 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_incomes_age_index                |            2 | age         | A         |         131 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_zipcode_sex_index                |            1 | zipcode     | A         |       21497 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_zipcode_sex_index                |            2 | sex         | A         |       43266 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_zipcode_age_index                |            1 | zipcode     | A         |       21497 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_zipcode_age_index                |            2 | age         | A         |      110259 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_zipcode_couple_index             |            1 | zipcode     | A         |       21497 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_zipcode_couple_index             |            2 | couple      | A         |       37085 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_zipcode_family_index             |            1 | zipcode     | A         |       21497 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_zipcode_family_index             |            2 | family      | A         |       38261 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_zipcode_type_index               |            1 | zipcode     | A         |       21497 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_zipcode_type_index               |            2 | type        | A         |       38549 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_zipcode_housing_index            |            1 | zipcode     | A         |       21497 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_zipcode_housing_index            |            2 | housing     | A         |       38841 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_department_sex_index             |            1 | department  | A         |          99 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_department_sex_index             |            2 | sex         | A         |         396 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_department_age_index             |            1 | department  | A         |          99 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_department_age_index             |            2 | age         | A         |        1393 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_department_couple_index          |            1 | department  | A         |          99 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_department_couple_index          |            2 | couple      | A         |         299 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_department_family_index          |            1 | department  | A         |          99 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_department_family_index          |            2 | family      | A         |         299 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_department_type_index            |            1 | department  | A         |          99 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_department_type_index            |            2 | type        | A         |         299 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_department_housing_index         |            1 | department  | A         |          99 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_department_housing_index         |            2 | housing     | A         |         299 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_housing_zipcode_sex_index    |            1 | age         | A         |          13 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_housing_zipcode_sex_index    |            2 | housing     | A         |          39 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_housing_zipcode_sex_index    |            3 | zipcode     | A         |      253187 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_housing_zipcode_sex_index    |            4 | sex         | A         |      539689 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_zipcode_type_sex_index       |            1 | age         | A         |          13 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_zipcode_type_sex_index       |            2 | zipcode     | A         |      110259 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_zipcode_type_sex_index       |            3 | type        | A         |      256352 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_zipcode_type_sex_index       |            4 | sex         | A         |      554275 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_family_zipcode_sex_index     |            1 | age         | A         |          13 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_family_zipcode_sex_index     |            2 | family      | A         |          39 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_family_zipcode_sex_index     |            3 | zipcode     | A         |      256352 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_family_zipcode_sex_index     |            4 | sex         | A         |      554275 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_couple_zipcode_sex_index     |            1 | age         | A         |          13 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_couple_zipcode_sex_index     |            2 | couple      | A         |          39 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_couple_zipcode_sex_index     |            3 | zipcode     | A         |      250099 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_couple_zipcode_sex_index     |            4 | sex         | A         |      525851 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_department_sex_housing_index |            1 | age         | A         |          13 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_department_sex_housing_index |            2 | department  | A         |        1393 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_department_sex_housing_index |            3 | sex         | A         |        5067 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_department_sex_housing_index |            4 | housing     | A         |       12192 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_type_department_sex_index    |            1 | age         | A         |          13 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_type_department_sex_index    |            2 | type        | A         |          39 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_type_department_sex_index    |            3 | department  | A         |        3913 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_type_department_sex_index    |            4 | sex         | A         |       12207 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_family_department_sex_index  |            1 | age         | A         |          13 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_family_department_sex_index  |            2 | family      | A         |          39 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_family_department_sex_index  |            3 | department  | A         |        3931 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_family_department_sex_index  |            4 | sex         | A         |       11759 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_sex_couple_department_index  |            1 | age         | A         |          13 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_sex_couple_department_index  |            2 | sex         | A         |          52 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_sex_couple_department_index  |            3 | couple      | A         |         132 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_age_sex_couple_department_index  |            4 | department  | A         |       10868 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | tmp_megabase_sms_data_1_sms_index                        |            1 | sms         | A         |     6836063 |     NULL | NULL   |      | BTREE      |         |                                        |
| megabase_sms_data_1 |          1 | contact_id                                               |            1 | contact_id  | A         |    20508191 |     NULL | NULL   |      | BTREE      |         |                                        |

第二个:

describe megabase_sms_thematic_repulse_1;
+------------------+------------+------+-----+---------+-------+
| Field            | Type       | Null | Key | Default | Extra |
+------------------+------------+------+-----+---------+-------+
| megabase_data_id | bigint(20) | NO   | MUL | NULL    |       |
| thematic_id      | int(11)    | NO   | MUL | NULL    |       |
+------------------+------------+------+-----+---------+-------+
2 rows in set (0.00 sec)

 SHOW INDEX FROM megabase_sms_thematic_repulse_1;
+---------------------------------+------------+------------------------------------------------------------+--------------+------------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table                           | Non_unique | Key_name                                                   | Seq_in_index | Column_name      | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+---------------------------------+------------+------------------------------------------------------------+--------------+------------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| megabase_sms_thematic_repulse_1 |          1 | tmp_megabase_sms_thematic_repulse_1_megabase_data_id_index |            1 | megabase_data_id | A         |           3 |     NULL | NULL   |      | BTREE      |         |               |
| megabase_sms_thematic_repulse_1 |          1 | tmp_megabase_sms_thematic_repulse_1_thematic_id_index      |            1 | thematic_id      | A         |           1 |     NULL | NULL   |      | BTREE      |         |               |
+---------------------------------+------------+------------------------------------------------------------+--------------+------------------+-----------+-------------+----------+--------+------+------------+---------+---------------+

我做错了什么？我可以做些什么来优化查询或数据库结构？

非常感谢

最佳答案

根据查询返回的行数，mysql 可能估计使用全扫描比使用索引更有效。

要缩小原因范围，请运行不带 where 子句的查询并查看是否正在使用索引。然后一个一个的加上where子句，看是哪一个导致索引不能用。该 where 子句可能过于通用 - 使其更有效地进行全表扫描，而不是使用索引。

如果假设年龄导致索引无法使用，您可以在 contact_id + age 上创建索引。

关于indexing - Mariadb:为什么我的查询没有使用索引？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/48719673/

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尝试使用“pdf_dart”库保存 pdf 时遇到问题。我认为问题与我从互联网下载以尝试附加到 pdf 的图像有关，但我不确定它是什么。代码 import 'dart:io'; import 'p
linux - 访问某些 index.php 或 index.html 时出现 Apache 403 错误，尽管每个 index.php 或 index.html 具有相似的权限
我的 Apache 服务器曾经可以正常工作，但它随机开始对几乎每个目录发出 403 错误。两个目录仍然有效，我怎样才能使/srv/www/htdocs 中的所有目录正常工作？我查看了两个可用目录的权
PHP 数组索引 : $array[$index] vs $array ["$index"] vs $array ["{$index}"]
这些索引到 PHP 数组的方法之间有什么区别(如果有的话): $array[$index] $array["$index"] $array["{$index}"] 我对性能和功能上的差异都感兴趣。更
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我有一个简单的结构，我想为其实现 Index，但作为 Rust 的新手，我在借用检查器方面遇到了很多麻烦。我的结构非常简单，我想让它存储一个开始值和步长值，然后当被 usize 索引时它应该返回 st
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我对 MarkLogic 中的 element-range-index 和 field-range-index 感到困惑。请借助示例来解释差异。最佳答案这两个都是标量索引:特定类型的基于值的排序
indexing - marklogic 中的 element-range-index 和 field-range-index 有什么区别？
我对 MarkLogic 中的 element-range-index 和 field-range-index 感到困惑。请借助示例来解释差异。最佳答案这两个都是标量索引:特定类型的基于值的排序
python - Pandas .at 抛出 ValueError : At based indexing on an integer index can only have integer indexers
所以我有一个 df，我在其中提取一个值以将其存储在另一个 df 中: import pandas as pd # Create data set d = {'foo':[100, 111, 222],
php - ci : google indexing address with index. php 但站点中没有与 index.php 的链接
我有一个由 codeigniter 编写的网站，我已经通过 htaccess 从地址中删除了 index.php RewriteCond $1 !^(index\.php|resources|robo
sql - MySQL: `... ADD INDEX(a); ... ADD INDEX(b);` 和 `... ADD INDEX(a,b);` 之间的区别？
谁能告诉我这两者有什么区别: ALTER TABLE x1 ADD INDEX(a); ALTER TABLE x1 ADD INDEX(b); 和 ALTER TABLE x1 ADD INDEX(
javascript - Firefox 上的嵌套 z-index 问题，较高的 z-index 落后于较低的 z-index
我在 Firefox 和其他浏览器上遇到嵌套 z-index 的问题，我有一个 div，z-index 为 30000，位于 label 下方> zindex 为 9000。我认为这是由 z-inde
c++ - 如果 index == 0，为什么 v [index] < v [index - 1] 返回 true？
Link to the function image编写了一个函数来查找中枢元素(起始/最低)的索引排序和旋转数组。我解决了这个问题并正在检查边缘情况，它甚至适用于索引为零的情况。任何人都可以解
python - 类型错误 : cannot perform __sub__ with this index type:
我正在尝试运行有关成人人口普查数据的示例代码。当我运行这段代码时: X_train, X_test, y_train, y_test = cross_validation.train_test_spl
apache - 如何 htaccess 将 index.html 重定向到 index.php 并将 index.php 重定向到/
我最近将我的 index.html 更改为 index.php - 我希望能够进行重定向以反射(reflect)这一点，然后还进行重写以强制 foo.com/index.php 成为 foo.com/
apache - 如何 htaccess 将 index.html 重定向到 index.php 并将 index.php 重定向到/
我最近将我的 index.html 更改为 index.php - 我希望能够进行重定向以反射(reflect)这一点，然后还进行重写以强制 foo.com/index.php 成为 foo.com/
python - <类 'pandas.indexes.numeric.Int64Index'> 的类型错误 : cannot do slice indexing on with these indexers [(2, )]
我有一个用户定义的函数，如下所示:- def genre(option,option_type,*limit): option_based = rank_data.loc[rank_data[
python - 减去索引 - TypeError : cannot perform __sub__ with this index type:
我有两个巨大的数据框我正在合并它们，但我不想有重复的列，因此我通过减去它们来选择列: cols_to_use=df_fin.columns-df_peers.columns.difference(['
javascript - 如何在 React Native 中使用 index.js 而不是 (index.ios.js, index.android.js) 进行跨平台应用程序？
感谢您从现在开始的回答，我是React Native的新手，我想做一个跨平台的应用所以我创建了index.js: import React from 'react'; import { Co
indexing - Field.Index.NOT_ANALYZED_NO_NORMS 是什么意思
我知道 not_analyzed 是什么意思。简而言之，该字段不会被指定的分析器标记化。然而，什么是 NO_NORMS 方法？我看到了文档，但请用简单的英语解释我。什么是索引时间字段和文档提升和字段

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