深入理解索引系列1：环境搭建

CREATE SCHEMA IF NOT EXISTS book;

USE book;

CREATE TABLE source_words(
word VARCHAR(50) NOT NULL,
INDEX(word)
)ENGINE=MyISAM;

LOAD DATA LOCAL INFILE ‘C:\\Users\\John\\Desktop\\source_words.txt‘ INTO TABLE source_words(word);

SELECT COUNT(*) FROM SOURCE_WORDS;

CREATE TABLE million_words(
id INT UNSIGNED NOT NULL AUTO_INCREMENT,
word VARCHAR(50) not null,
primary key (id),
UNIQUE INDEX (word)) ENGINE=INNODB;

INSERT INTO million_words(word)
SELECT DISTINCT word FROM source_words;

INSERT INTO million_words(word)
SELECT DISTINCT REVERSE(word) FROM source_words WHERE REVERSE(word) NOT IN (SELECT word FROM source_words);

SELECT @cnt := COUNT(*) FROM million_words;
--59572

SELECT @diff := 1000000- @cnt;
--940428


SET @sql = CONCAT("
INSERT INTO million_words(word)
SELECT DISTINCT CONCAT(word,‘X1Y‘) FROM source_words LIMIT",@diff);

PREPARE cmd FROM @sql;

EXECUTE cmd;

SELECT COUNT(*) FROM million_words;
--89358