我使用MySQL 5.7.10,存儲引擎是InnoDB。 以下是SQL。
1.創建表爲什麼這個查詢不使用鍵(MySQL 5.7空間)?
CREATE TABLE `geo` (
`id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
`geo` GEOMETRY NOT NULL,
PRIMARY KEY (`id`),
SPATIAL INDEX `geo` (`geo`)
)
COLLATE='utf8mb4_general_ci'
ENGINE=InnoDB
AUTO_INCREMENT=1
2.插入數據
insert into geo(geo) values(ST_GeomFromText('POINT(108.875000 34.216020)'));
insert into geo(geo) values(ST_GeomFromText('POINT(109.569098 36.646357)'));
insert into geo(geo) values(ST_GeomFromText('POINT(109.550988 36.633384)'));
insert into geo(geo) values(ST_GeomFromText('POINT(109.472800 36.624116)'));
insert into geo(geo) values(ST_GeomFromText('POINT(109.487460 36.563614)'));
insert into geo(geo) values(ST_GeomFromText('POINT(109.532016 36.686191)'));
insert into geo(geo) values(ST_GeomFromText('POINT(109.319010 36.987505)'));
3.創建一個多邊形
SET @g3 = ST_GeomFromText('Polygon((108 36.5,108 36.7,109.5 36.7,109.5 36.5,108 36.5))');
4.講解SQL
mysql> explain select st_x(geo),st_y(geo) from geo where mbrcontains(@g3,geo)>0\G
*************************** 1. row ***************************
id: 1
select_type: SIMPLE
table: geo
partitions: NULL
type: ALL
possible_keys: NULL
key: NULL
key_len: NULL
ref: NULL
rows: 8
filtered: 100.00
Extra: Using where
1 row in set, 1 warning (0.00 sec)
mysql> show warnings\G
*************************** 1. row ***************************
Level: Note
Code: 1003
Message: /* select#1 */ select st_x(`map`.`geo`.`geo`) AS `st_x(geo)`,st_y(`map`.`geo`.`geo`) AS `st_y(geo)` from `map`.`geo` where (mbrcontains((@`g3`),`map`.`geo`.`geo`) > 0)
1 row in set (0.00 sec)
爲什麼沒有按」 t thi s查詢使用密鑰?
你'EXPLAIN'返回一個警告。它以前如何? (查詢後運行'SHOW WARNINGS'顯示警告。) – duskwuff
'mysql> show warnings \ G ************************** * 1. row *************************** 等級:備註 代碼:1003 消息:/ * select#1 */select st_x(''map'.'geo'.'geo')AS'st_x(geo)',st_y('map'.'geo'.'geo')AS'st_y(geo)'來自 m'map' .'geo'其中(mbrcontains((@'g3'),'map'.'geo'.''''>> 0) 集合中的第1行(0.00秒)' – user2400825
請在您的問題中包含警告,而不是在評論中。 – duskwuff