MySQL explain:修订间差异
已建立頁面,內容為 "<pre> mysql> explain SELECT COUNT(*) FROM vehicle_prod WHERE fin LIKE '%00000'; +----+-------------+--------------+------------+-------+---------------+-------------…" |
无编辑摘要 |
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第1行: | 第1行: | ||
<pre> | <pre> | ||
mysql> explain SELECT COUNT(*) FROM vehicle_prod WHERE fin LIKE '%00000' | mysql> explain SELECT COUNT(*) FROM vehicle_prod WHERE fin LIKE '%00000' \G | ||
*************************** 1. row *************************** | |||
id: 1 | |||
select_type: SIMPLE | |||
table: vehicle_prod | |||
partitions: NULL | |||
type: index | |||
possible_keys: NULL | |||
key: idx_vehicle_prod_fin | |||
key_len: 203 | |||
ref: NULL | |||
rows: 3182812 | |||
filtered: 11.11 | |||
Extra: Using where; Using index | |||
1 row in set, 1 warning (0.00 sec) | 1 row in set, 1 warning (0.00 sec) | ||
</pre> | </pre> | ||
其中: | |||
*id select_id The SELECT identifier | |||
*select_type None The SELECT type | |||
*table table_name The table for the output row | |||
*partitions partitions The matching partitions | |||
*type access_type The join type | |||
*possible_keys possible_keys The possible indexes to choose | |||
*key key The index actually chosen | |||
*key_len key_length The length of the chosen key | |||
*ref ref The columns compared to the index | |||
*rows rows Estimate of rows to be examined | |||
*filtered filtered Percentage of rows filtered by table condition | |||
*Extra None Additional information | |||
[[Category:Datebase]] | [[Category:Datebase]] |
2018年9月18日 (二) 09:16的版本
mysql> explain SELECT COUNT(*) FROM vehicle_prod WHERE fin LIKE '%00000' \G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: vehicle_prod partitions: NULL type: index possible_keys: NULL key: idx_vehicle_prod_fin key_len: 203 ref: NULL rows: 3182812 filtered: 11.11 Extra: Using where; Using index 1 row in set, 1 warning (0.00 sec)
其中:
- id select_id The SELECT identifier
- select_type None The SELECT type
- table table_name The table for the output row
- partitions partitions The matching partitions
- type access_type The join type
- possible_keys possible_keys The possible indexes to choose
- key key The index actually chosen
- key_len key_length The length of the chosen key
- ref ref The columns compared to the index
- rows rows Estimate of rows to be examined
- filtered filtered Percentage of rows filtered by table condition
- Extra None Additional information