Help Center/ GaussDB(DWS)/ More Documents/ SQL Syntax Reference (Kuala Lumpur Region)/ Functions and Operators/ Text Search Functions and Operators
Updated on 2022-08-16 GMT+08:00
View PDF
Share

Text Search Functions and Operators

Text Search Operators

  • @@

    Description: Specifies whether the tsvector-typed words match the tsquery-typed words.

    For example:

    1
2
3
4
5
    		 
    SELECT to_tsvector('fat cats ate rats') @@ to_tsquery('cat & rat') AS RESULT;
 result 
--------
 t
(1 row)
  • @@@

    Description: Synonym for @@

    For example:

    1
2
3
4
5
    		 
    SELECT to_tsvector('fat cats ate rats') @@@ to_tsquery('cat & rat') AS RESULT;
 result 
--------
 t
(1 row)
  • ||

    Description: Connects two tsvector-typed words.

    For example:

    1
2
3
4
5
    		 
    SELECT 'a:1 b:2'::tsvector || 'c:1 d:2 b:3'::tsvector AS RESULT;
          result           
---------------------------
 'a':1 'b':2,5 'c':3 'd':4
(1 row)
  • &&

    Description: Performs the AND operation on two tsquery-typed words.

    For example:

    1
2
3
4
5
    		 
    SELECT 'fat | rat'::tsquery && 'cat'::tsquery AS RESULT;
          result           
---------------------------
 ( 'fat' | 'rat' ) & 'cat'
(1 row)
  • ||

    Description: Performs the OR operation on two tsquery-typed words.

    For example:

    1
2
3
4
5
    		 
    SELECT 'fat | rat'::tsquery || 'cat'::tsquery AS RESULT;
          result           
---------------------------
 ( 'fat' | 'rat' ) | 'cat'
(1 row)
  • !!

    Description: NOT a tsquery

    For example:

    1
2
3
4
5
    		 
    SELECT !! 'cat'::tsquery AS RESULT;
 result 
--------
 !'cat'
(1 row)
  • @>

    Description: Specifies whether a tsquery-typed word contains another tsquery-typed word.

    For example:

    1
2
3
4
5
    		 
    SELECT 'cat'::tsquery @> 'cat & rat'::tsquery AS RESULT;
 result 
--------
 f
(1 row)
  • <@

    Description: Specifies whether a tsquery-typed word is contained in another tsquery-typed word.

    For example:

    1
2
3
4
5
    		 
    SELECT 'cat'::tsquery <@ 'cat & rat'::tsquery AS RESULT;
 result 
--------
 t
(1 row)

In addition to the preceding operators, the ordinary B-tree comparison operators (including = and <) are defined for types tsvector and tsquery.

Text search functions

  • get_current_ts_config()

    Description: Gets default text search configuration.

    Return type: regconfig

    For example:

    1
2
3
4
5
    		 
    SELECT get_current_ts_config();
 get_current_ts_config 
-----------------------
 english
(1 row)
  • length(tsvector)

    Description: Number of lexemes in a tsvector-typed word.

    Return type: integer

    For example:

    1
2
3
4
5
    		 
    SELECT length('fat:2,4 cat:3 rat:5A'::tsvector);
 length 
--------
      3
(1 row)
  • numnode(tsquery)

    Description: Number of lexemes plus tsquery operators

    Return type: integer

    For example:

    1
2
3
4
5
    		 
    SELECT numnode('(fat & rat) | cat'::tsquery);
 numnode 
---------
       5
(1 row)
  • plainto_tsquery([ config regconfig , ] query text)

    Description: Generates tsquery lexemes without punctuation.

    Return type: tsquery

    For example:

    1
2
3
4
5
    		 
    SELECT plainto_tsquery('english', 'The Fat Rats');
 plainto_tsquery 
-----------------
 'fat' & 'rat'
(1 row)
  • querytree(query tsquery)

    Description: Gets indexable part of a tsquery.

    Return type: text

    For example:

    1
2
3
4
5
    		 
    SELECT querytree('foo & ! bar'::tsquery);
 querytree 
-----------
 'foo'
(1 row)
  • setweight(tsvector, "char")

    Description: Assigns weight to each element of tsvector.

    Return type: tsvector

    For example:

    1
2
3
4
5
    		 
    SELECT setweight('fat:2,4 cat:3 rat:5B'::tsvector, 'A');
           setweight           
-------------------------------
 'cat':3A 'fat':2A,4A 'rat':5A
(1 row)
  • strip(tsvector)

    Description: Removes positions and weights from tsvector.

    Return type: tsvector

    For example:

    1
2
3
4
5
    		 
    SELECT strip('fat:2,4 cat:3 rat:5A'::tsvector);
       strip       
-------------------
 'cat' 'fat' 'rat'
(1 row)
  • to_tsquery([ config regconfig , ] query text)

    Description: Normalizes words and converts them to tsquery.

    Return type: tsquery

    For example:

    1
2
3
4
5
    		 
    SELECT to_tsquery('english', 'The & Fat & Rats');
  to_tsquery   
---------------
 'fat' & 'rat'
(1 row)
  • to_tsvector([ config regconfig , ] document text)

    Description: Reduces document text to tsvector.

    Return type: tsvector

    For example:

    1
2
3
4
5
    		 
    SELECT to_tsvector('english', 'The Fat Rats');
   to_tsvector   
-----------------
 'fat':2 'rat':3
(1 row)
  • ts_headline([ config regconfig, ] document text, query tsquery [, options text ])

    Description: Highlights a query match.

    Return type: text

    For example:

    1
2
3
4
5
    		 
    SELECT ts_headline('x y z', 'z'::tsquery);
 ts_headline  
--------------
 x y <b>z</b>
(1 row)
  • ts_rank([ weights float4[], ] vector tsvector, query tsquery [, normalization integer ])

    Description: Ranks document for query.

    Return type: float4

    For example:

    1
2
3
4
5
    		 
    SELECT ts_rank('hello world'::tsvector, 'world'::tsquery);
 ts_rank  
----------
 .0607927
(1 row)
  • ts_rank_cd([ weights float4[], ] vector tsvector, query tsquery [, normalization integer ])

    Description: Ranks document for query using cover density.

    Return type: float4

    For example:

    1
2
3
4
5
    		 
    SELECT ts_rank_cd('hello world'::tsvector, 'world'::tsquery);
 ts_rank_cd 
------------
          0
(1 row)
  • ts_rewrite(query tsquery, target tsquery, substitute tsquery)

    Description: Replaces tsquery-typed word.

    Return type: tsquery

    For example:

    1
2
3
4
5
    		 
    SELECT ts_rewrite('a & b'::tsquery, 'a'::tsquery, 'foo|bar'::tsquery);
       ts_rewrite        
-------------------------
 'b' & ( 'foo' | 'bar' )
(1 row)
  • ts_rewrite(query tsquery, select text)

    Description: Replaces tsquery data in the target with the result of a SELECT command.

    Return type: tsquery

    For example:

    1
2
3
4
5
    		 
    SELECT ts_rewrite('world'::tsquery, 'select ''world''::tsquery, ''hello''::tsquery');
 ts_rewrite 
------------
 'hello'
(1 row)

Text Search Debugging Functions

  • ts_debug([ config regconfig, ] document text, OUT alias text, OUT description text, OUT token text, OUT dictionaries regdictionary[], OUT dictionary regdictionary, OUT lexemes text[])

    Description: Tests a configuration.

    Return type: setof record

    For example:

    1
2
3
4
5
6
7
8
9
    		 
    SELECT ts_debug('english', 'The Brightest supernovaes');
                                     ts_debug                                      
-----------------------------------------------------------------------------------
 (asciiword,"Word, all ASCII",The,{english_stem},english_stem,{})
 (blank,"Space symbols"," ",{},,)
 (asciiword,"Word, all ASCII",Brightest,{english_stem},english_stem,{brightest})
 (blank,"Space symbols"," ",{},,)
 (asciiword,"Word, all ASCII",supernovaes,{english_stem},english_stem,{supernova})
(5 rows)
  • ts_lexize(dict regdictionary, token text)

    Description: Tests a data dictionary.

    Return type: text[]

    For example:

    1
2
3
4
5
    		 
    SELECT ts_lexize('english_stem', 'stars');
 ts_lexize 
-----------
 {star}
(1 row)
  • ts_parse(parser_name text, document text, OUT tokid integer, OUT token text)

    Description: Tests a parser.

    Return type: setof record

    For example:

    1
2
3
4
5
6
7
8
    		 
    SELECT ts_parse('default', 'foo - bar');
 ts_parse  
-----------
 (1,foo)
 (12," ")
 (12,"- ")
 (1,bar)
(4 rows)
  • ts_parse(parser_oid oid, document text, OUT tokid integer, OUT token text)

    Description: Tests a parser.

    Return type: setof record

    For example:

    1
2
3
4
5
6
7
8
    		 
    SELECT ts_parse(3722, 'foo - bar');
 ts_parse  
-----------
 (1,foo)
 (12," ")
 (12,"- ")
 (1,bar)
(4 rows)
  • ts_token_type(parser_name text, OUT tokid integer, OUT alias text, OUT description text)

    Description: Gets token types defined by parser.

    Return type: setof record

    For example:

     1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
    		 
    SELECT ts_token_type('default');
                        ts_token_type                         
--------------------------------------------------------------
 (1,asciiword,"Word, all ASCII")
 (2,word,"Word, all letters")
 (3,numword,"Word, letters and digits")
 (4,email,"Email address")
 (5,url,URL)
 (6,host,Host)
 (7,sfloat,"Scientific notation")
 (8,version,"Version number")
 (9,hword_numpart,"Hyphenated word part, letters and digits")
 (10,hword_part,"Hyphenated word part, all letters")
 (11,hword_asciipart,"Hyphenated word part, all ASCII")
 (12,blank,"Space symbols")
 (13,tag,"XML tag")
 (14,protocol,"Protocol head")
 (15,numhword,"Hyphenated word, letters and digits")
 (16,asciihword,"Hyphenated word, all ASCII")
 (17,hword,"Hyphenated word, all letters")
 (18,url_path,"URL path")
 (19,file,"File or path name")
 (20,float,"Decimal notation")
 (21,int,"Signed integer")
 (22,uint,"Unsigned integer")
 (23,entity,"XML entity")
(23 rows)
  • ts_token_type(parser_oid oid, OUT tokid integer, OUT alias text, OUT description text)

    Description: Gets token types defined by parser.

    Return type: setof record

    For example:

     1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
    		 
    SELECT ts_token_type(3722);
                        ts_token_type                         
--------------------------------------------------------------
 (1,asciiword,"Word, all ASCII")
 (2,word,"Word, all letters")
 (3,numword,"Word, letters and digits")
 (4,email,"Email address")
 (5,url,URL)
 (6,host,Host)
 (7,sfloat,"Scientific notation")
 (8,version,"Version number")
 (9,hword_numpart,"Hyphenated word part, letters and digits")
 (10,hword_part,"Hyphenated word part, all letters")
 (11,hword_asciipart,"Hyphenated word part, all ASCII")
 (12,blank,"Space symbols")
 (13,tag,"XML tag")
 (14,protocol,"Protocol head")
 (15,numhword,"Hyphenated word, letters and digits")
 (16,asciihword,"Hyphenated word, all ASCII")
 (17,hword,"Hyphenated word, all letters")
 (18,url_path,"URL path")
 (19,file,"File or path name")
 (20,float,"Decimal notation")
 (21,int,"Signed integer")
 (22,uint,"Unsigned integer")
 (23,entity,"XML entity")
(23 rows)
  • ts_stat(sqlquery text, [ weights text, ] OUT word text, OUT ndoc integer, OUT nentry integer)

    Description: Gets statistics of a tsvector column.

    Return type: setof record

    For example:

    1
2
3
4
5
6
    		 
    SELECT ts_stat('select ''hello world''::tsvector');
   ts_stat   
-------------
 (world,1,1)
 (hello,1,1)
(2 rows)
Parent topic: Functions and Operators