Remove jsonb array element by value

问题

I did figure out how to remove a value from an array for a single record, but how to do it for many of them. The problem is in the way how I use the subquery. As it has to return only single element. Maybe my approach is wrong.


    Given input: '{attributes:['is_new', 'is_old']}'
    Expected result '{attributes: ['is_old']}' #remove 'is_new' from jsonb array


    Real example:
    #   sku  |           properties 
    # -------+--------------------------------
    #  nu3_1 | {                             +
    #        |     "name": "silly_hodgkin",  +
    #        |     "type": "food",           +
    #        |     "attributes": [           +
    #        |         "is_gluten_free",     +
    #        |         "is_lactose_free",    +
    #        |         "is_new"              +
    #        |     ]                         +
    #        | }


#Query that removes single array element:

SELECT c.sku, jsonb_agg(el) FROM
catalog c JOIN (select sku, jsonb_array_elements_text(properties->'attributes') as el from catalog) c2 ON c.sku=c2.sku where el  'is_new'
GROUP BY c.sku;

#Update query that removes single array element in single record

UPDATE catalog SET properties=jsonb_set(properties, '{attributes}', (
    SELECT jsonb_agg(el) FROM
    catalog c JOIN (select sku, jsonb_array_elements_text(properties->'attributes') as el from catalog) c2 ON c.sku=c2.sku
    WHERE el  'is_new' AND c.sku='nu3_1'
    GROUP BY c.sku
    )
) WHERE sku='nu3_1';

The question again is. How to remove jsonb array element by value for many database records?

回答1:

Use jsonb_set() and the delete operator -:

update catalog
set properties = 
    jsonb_set(properties, '{attributes}', (properties->'attributes') - 'is_new');

Test it in rextester.

回答2:

So, I believe QRY you are looking for is:

with q as (
  select distinct sku, jsonb_set(properties,'{attributes}',jsonb_agg(el) over (partition by sku),false) new_properties
  from (
    select 
      sku, jsonb_array_elements_text(properties->'attributes') as el, properties
    from catalog
  ) p
  where el != 'is_new'
)
update catalog set properties = q.new_properties from q where catalog.sku = q.sku
;

be aware that I assumed your sku is at least UK!

回答3:

Your solution works + you pointed me to some new stuff like window functions and give me an idea for alternative solution:

WITH q as (
  SELECT c.sku as sku,  jsonb_set(properties, '{attributes}', jsonb_agg(el)) as new_properties
    FROM catalog c JOIN (select sku, jsonb_array_elements_text(properties->'attributes') as el from catalog) c2 ON c.sku=c2.sku where el != 'is_new'
    GROUP BY c.sku
)
UPDATE catalog SET properties=q.new_properties FROM q WHERE catalog.sku=q.sku;

来源：https://stackoverflow.com/questions/40285583/remove-jsonb-array-element-by-value

标签

arrays

json

postgresql

jsonb