建表
CREATE TABLE USERINFO(
ID INT NOT NULL PRIMARY KEY,
NAME VARCHAR(20),
AGE INT,
ADDR VARCHAR(100)
);
插入數據
INSERT INTO USERINFO
VALUES
(1,'Emma',20,'aaaaaaaaaaaa'),
(2,'Lisa',21,'bbbbbbbbbbb'),
(3,'Jekyll',30,'ccccccccccc'),
(4,'Hyde',28,'dddddddddddd'),
(5,'Lucy',16,'eeeeeeeeeeee'),
(6,'Eric',17,'ffffffffffffffff'),
(7,'Amy',19,'ggggggggggggggggg');
創建索引
CREATE INDEX 索引名 ON 表名(列名);
CREATE INDEX idx_id ON userinfo(id);
創建組合索引
CREATE INDEX 索引名 ON 表名(列名1,列名2);
CREATE INDEX idx_id$name ON userinfo(id,name);
查看索引
SHOW INDEX FROM 表名;
SHOW INDEX FROM userinfo;
刪除索引
DROP INDEX 索引名 ON 表名;
DROP INDEX idx_id ON userinfo;