How to make unstructured array of object to row?

All we need is an easy explanation of the problem, so here it is.

c.data is jsonb object, like this: {programs:[{...},{...}]}

c.data->'programs' is jsonb array, like this [{a:1},{b:2},{c:3,d:4}] or null

Already tried this:

SELECT p
FROM Clients c , jsonb_array_elements(c.data->'programs') p

or this

SELECT p
FROM Clients c , jsonb_array_elements(COALESCE(c.data->'programs','[]'::JSONB)) p

but it shows an error:

[22023] ERROR: cannot extract elements from a scalar

how can I retrieve the object inside data->'programs' as rows of object?

How to solve :

I know you bored from this bug, So we are here to help you! Take a deep breath and look at the explanation of your problem. We have many solutions to this problem, But we recommend you to use the first method because it is tested & true method that will 100% work for you.

Method 1

You can use a JSON path instead, using the jsonb_path_query function.

SELECT p
FROM Clients c
CROSS JOIN LATERAL jsonb_path_query(c.data, '$.programs') p

db<>fiddle

Method 2

Nevermind, found the answer, must filter the null first

SELECT p
FROM Clients c, jsonb_array_elements(c.data->'programs') p
WHERE (c.data->>'programs') <> 'null'
-- or LENGTH(c.data->>'programs') > 0

Note: Use and implement method 1 because this method fully tested our system.
Thank you 🙂

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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