从JSON postgres数组中获取元素

Question

I have a column x with data type jsonb

and the value looks like:

[  
    [{"string":"whateverstring1"}],
    [{"string":"whateverstring2"}]
]

How to return each element of the array?

Something like this: " whateverstring1 "," whateverstring2 "

Answer 1

demo:db<>fiddle

SELECT jsonb_array_elements(jsonb) -> 0 -> 'string' 
FROM (
    SELECT '[[{"string":"whateverstring1"}],[{"string":"whateverstring2"}]]'::jsonb
) s

1. jsonb_array_elements extract each element into one row
2. -> 0 gives the first element of the nested arrays which is {"string":"whateverstring1"}
3. -> 'string' gives the value of the elements