openGauss每日一练第 20 天

opengauss 学习第二十天

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

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

SELECT 'a fat cat sat on a mat and ate a fat rat'::tsvector @@ 'cat & rat'::tsquery AS RESULT;
SELECT 'fat & cow'::tsquery @@ 'a fat cat sat on a mat and ate a fat rat'::tsvector AS RESULT;
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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

CREATE SCHEMA tsearch;
CREATE TABLE tsearch.pgweb(id int, body text, title text, last_mod_date date);
INSERT INTO tsearch.pgweb 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');
INSERT INTO tsearch.pgweb VALUES(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');
INSERT INTO tsearch.pgweb VALUES(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');
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CREATE INDEX pgweb_idx_1 ON tsearch.pgweb USING gin(to_tsvector('english', body));
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3.创建GIN索引

CREATE INDEX pgweb_idx_3 ON tsearch.pgweb USING gin(to_tsvector('english', title || ' ' ||
body));
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4.清理数据

drop schema tsearch cascade;
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第二十天学习openGauss 全文检索;

每天进步一点点，期待明天加油！