[prev] 72 [next]

Similarity Retrieval in PostgreSQL

PostgreSQL has always supported simple "similarity" on strings 

-- for most SQL implementations
select * from Students where name like '%oo%';
-- and PostgreSQL-specific
select * from Students where name ~ '[Ss]mit';


Also provides support for ranked similarity on text values

  • using tsvector data type  (stemmed, stopped feature vector for text)
  • using tsquery data type  (stemmed, stopped feature vector for strings)
  • using @@ similarity operator