openGauss 每日一练第 20 天打卡，我来了！又可以学习，真开心~

学习

今天第 20 课，学习openGauss全文检索。

openGauss提供了两种数据类型用于支持全文检索。tsvector类型表示为文本搜索优化的文件格式，tsquery类型表示文本查询！

课后作业

1.用tsvector @@ tsquery和tsquery @@ tsvector完成两个基本文本匹配

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SELECT to_tsvector('dog roots pig red ate') @@ to_tsquery('dog & root') AS RESULT;
SELECT to_tsquery('dog & root') @@ to_tsvector('dog roots pig red ate') AS RESULT;

2.创建表且至少有两个字段的类型为 text类型，在创建索引前进行全文检索

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CREATE SCHEMA lucifer;
CREATE TABLE lucifer.lucifer(id int, body text, title text, last_mod_date date);
INSERT INTO lucifer.lucifer VALUES(1, 'China, officially the People''s Republic of China(PRC), located in Asia, is the world''s most populous state.', 'China', '2010-1-1'),(2, 'America is a rock band, formed in England in 1970 by multi-instrumentalists Dewey Bunnell, Dan Peek, and Gerry Beckley.', 'America', '2010-1-1'),(3, 'England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west.', 'England','2010-1-1');

SELECT id, body, title FROM lucifer.lucifer WHERE to_tsvector(body) @@ to_tsquery('america');
SELECT title FROM lucifer.lucifer WHERE to_tsvector(title || ' ' || body) @@ to_tsquery('china & asia');

3.创建GIN索引

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CREATE INDEX lucifer_idx_1 ON lucifer.lucifer USING gin(to_tsvector('english', body));

4.清理数据

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drop schema lucifer cascade;

写在最后

今天的作业打卡结束！🎉