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postgresqljsonb

How to transform jsonb array of array into records


Given an array of objects, we can turn that into recordset very easily with jsonb_to_recordset.

select * from jsonb_to_recordset($$[
  {"name": "name01", "age": 12},
  {"name": "name02", "age": 14},
  {"name": "name03", "age": 16},
  {"name": "name04", "age": 18}
]$$) as (name text, age int)


name   |age |
-------|----|
name01 |12  |
name02 |14  |
name03 |16  |
name04 |18  |

But what can we do if we prefer source data in the form of array of array ? How to transform below query to yield similar result to the above ?

select array['name', 'age']  "labels"
     , x.value               "values" 
from jsonb_array_elements($$[
  ["name01", 12],
  ["name02", 14],
  ["name03", 16],
  ["name04", 18]
]$$) x


labels     |values         |
-----------|---------------|
{name,age} |["name01", 12] |
{name,age} |["name02", 14] |
{name,age} |["name03", 16] |
{name,age} |["name04", 18] |

Solution

  • You could use ->>:

    select x.value->>0 AS name,
           x.value->>1 AS age     
    from jsonb_array_elements($$[
      ["name01", 12],
      ["name02", 14],
      ["name03", 16],
      ["name04", 18]
    ]$$) x;
    

    Output:

    +--------+-----+
    |  name  | age |
    +--------+-----+
    | name01 |  12 |
    | name02 |  14 |
    | name03 |  16 |
    | name04 |  18 |
    +--------+-----+
    

    DBFiddle Demo