9.13. Text Search Functions and Operators

Table 9.37, Table 9.38 and Table 9.39 summarize the functions and operators that are provided for full text searching. See Chapter 12 for a detailed explanation of PostgreSQL's text search facility.

Table 9.37. Text Search Operators

@@tsvector matches tsquery ?to_tsvector('fat cats ate rats') @@ to_tsquery('cat & rat')t
@@@deprecated synonym for @@to_tsvector('fat cats ate rats') @@@ to_tsquery('cat & rat')t
||concatenate tsvectors'a:1 b:2'::tsvector || 'c:1 d:2 b:3'::tsvector'a':1 'b':2,5 'c':3 'd':4
&&AND tsquerys together'fat | rat'::tsquery && 'cat'::tsquery( 'fat' | 'rat' ) & 'cat'
||OR tsquerys together'fat | rat'::tsquery || 'cat'::tsquery( 'fat' | 'rat' ) | 'cat'
!!negate a tsquery!! 'cat'::tsquery!'cat'
@>tsquery contains another ?'cat'::tsquery @> 'cat & rat'::tsqueryf
<@tsquery is contained in ?'cat'::tsquery <@ 'cat & rat'::tsqueryt


The tsquery containment operators consider only the lexemes listed in the two queries, ignoring the combining operators.

In addition to the operators shown in the table, the ordinary B-tree comparison operators (=, <, etc) are defined for types tsvector and tsquery. These are not very useful for text searching but allow, for example, unique indexes to be built on columns of these types.

Table 9.38. Text Search Functions

FunctionReturn TypeDescriptionExampleResult
get_current_ts_config()regconfigget default text search configurationget_current_ts_config()english
length(tsvector)integernumber of lexemes in tsvectorlength('fat:2,4 cat:3 rat:5A'::tsvector)3
numnode(tsquery)integernumber of lexemes plus operators in tsquery numnode('(fat & rat) | cat'::tsquery)5
plainto_tsquery([ config regconfig , ] query text)tsqueryproduce tsquery ignoring punctuationplainto_tsquery('english', 'The Fat Rats')'fat' & 'rat'
querytree(query tsquery)textget indexable part of a tsqueryquerytree('foo & ! bar'::tsquery)'foo'
setweight(tsvector, "char")tsvectorassign weight to each element of tsvectorsetweight('fat:2,4 cat:3 rat:5B'::tsvector, 'A')'cat':3A 'fat':2A,4A 'rat':5A
strip(tsvector)tsvectorremove positions and weights from tsvectorstrip('fat:2,4 cat:3 rat:5A'::tsvector)'cat' 'fat' 'rat'
to_tsquery([ config regconfig , ] query text)tsquerynormalize words and convert to tsqueryto_tsquery('english', 'The & Fat & Rats')'fat' & 'rat'
to_tsvector([ config regconfig , ] document text)tsvectorreduce document text to tsvectorto_tsvector('english', 'The Fat Rats')'fat':2 'rat':3
ts_headline([ config regconfig, ] document text, query tsquery [, options text ])textdisplay a query matchts_headline('x y z', 'z'::tsquery)x y <b>z</b>
ts_rank([ weights float4[], ] vector tsvector, query tsquery [, normalization integer ])float4rank document for queryts_rank(textsearch, query)0.818
ts_rank_cd([ weights float4[], ] vector tsvector, query tsquery [, normalization integer ])float4rank document for query using cover densityts_rank_cd('{0.1, 0.2, 0.4, 1.0}', textsearch, query)2.01317
ts_rewrite(query tsquery, target tsquery, substitute tsquery)tsqueryreplace target with substitute within queryts_rewrite('a & b'::tsquery, 'a'::tsquery, 'foo|bar'::tsquery)'b' & ( 'foo' | 'bar' )
ts_rewrite(query tsquery, select text)tsqueryreplace using targets and substitutes from a SELECT commandSELECT ts_rewrite('a & b'::tsquery, 'SELECT t,s FROM aliases')'b' & ( 'foo' | 'bar' )
tsvector_update_trigger()triggertrigger function for automatic tsvector column updateCREATE TRIGGER ... tsvector_update_trigger(tsvcol, 'pg_catalog.swedish', title, body)
tsvector_update_trigger_column()triggertrigger function for automatic tsvector column updateCREATE TRIGGER ... tsvector_update_trigger_column(tsvcol, configcol, title, body)


All the text search functions that accept an optional regconfig argument will use the configuration specified by default_text_search_config when that argument is omitted.

The functions in Table 9.39 are listed separately because they are not usually used in everyday text searching operations. They are helpful for development and debugging of new text search configurations.

Table 9.39. Text Search Debugging Functions

FunctionReturn TypeDescriptionExampleResult
ts_debug([ config regconfig, ] document text, OUT alias text, OUT description text, OUT token text, OUT dictionaries regdictionary[], OUT dictionary regdictionary, OUT lexemes text[])setof recordtest a configurationts_debug('english', 'The Brightest supernovaes')(asciiword,"Word, all ASCII",The,{english_stem},english_stem,{}) ...
ts_lexize(dict regdictionary, token text)text[]test a dictionaryts_lexize('english_stem', 'stars'){star}
ts_parse(parser_name text, document text, OUT tokid integer, OUT token text)setof recordtest a parserts_parse('default', 'foo - bar')(1,foo) ...
ts_parse(parser_oid oid, document text, OUT tokid integer, OUT token text)setof recordtest a parserts_parse(3722, 'foo - bar')(1,foo) ...
ts_token_type(parser_name text, OUT tokid integer, OUT alias text, OUT description text)setof recordget token types defined by parserts_token_type('default')(1,asciiword,"Word, all ASCII") ...
ts_token_type(parser_oid oid, OUT tokid integer, OUT alias text, OUT description text)setof recordget token types defined by parserts_token_type(3722)(1,asciiword,"Word, all ASCII") ...
ts_stat(sqlquery text, [ weights text, ] OUT word text, OUT ndoc integer, OUT nentry integer)setof recordget statistics of a tsvector columnts_stat('SELECT vector from apod')(foo,10,15) ...