在 postgres 中对 jsonb 数组数据进行索引的 ILIKE 查询

Question

I have table in which has city as jsonb column which has json array like below

[{"name":"manchester",..},{"name":"liverpool",....}]

now I want to query table on "name" column with ILIKE query.

I have tried with below but it is not working for me

select * from data where city->>'name' ILIKE '%man%'

while i know, I can search with exact match by below query

select * from data where city->>'name' @> 'manchester'

Also I know we can jsonb functions to make it flat data and search but it will not use than indexing.

is there anyway to search data with ilike in a way it also use indexing?

Answer 1

Index support will be difficult; for that, a schema that adheres to the first normal form would be beneficial.

Other than that, you can use the JSONPATH language from v12 on:

WITH t(c) AS (
   SELECT '[{"name":"manchester"},{"name":"liverpool"}]'::jsonb
)
SELECT jsonb_path_exists(
          c,
          '$.**.name ? (@ like_regex "man" flag "i")'::jsonpath
       )
FROM t;

 jsonb_path_exists 
═══════════════════
 t
(1 row)

Answer 2

You should really store your data differently.

You can do the ilike query "naturally" but without index support, like this:

select * from data where exists (select 1 from jsonb_array_elements(city) f(x) where x->>'name' ILIKE '%man%');

You can get index support like this:

create index on data using gin ((city::text) gin_trgm_ops);
select * from data where city::text ilike '%man%';

But it will find matches within the text of the keys, as well as the values, and using irrelevant keys/values of any are present. You could get around this by creating a function that returns just the values, all banged together into one string, and then use a functional index. But the index will get less effective as the length of the string gets longer, as there will be more false positives that need to be tracked down and weeded out.

create or replace function concat_val(jsonb, text) returns text immutable language sql as $$
    select string_agg(x->>$2,'   ') from jsonb_array_elements($1) f(x)
$$ parallel safe;

create index on data using gin (concat_val(city,'name')  gin_trgm_ops);

select * from data where concat_val(city,'name') ilike '%man%';

You should really store your data differently.