JSON Functions

json_extract_path_text(json text, json_path text)

Extracts JSON string from a JSON string based on json path specified and returns JSON string pointed to by JSONPath. Returns null if either argument is null.

Parameters:
  • json – JSON string
  • json_path – JSONpath
Return type:

text

Example:
select json_extract_path_text('{"test" : {"key" : "tajo"}}','$.test.key');
> tajo
json_array_get(json_array text, index int4)

Returns the element at the specified index into the JSON array. This function returns an element indexed from the end of an array with a negative index, and null if the element at the specified index doesn’t exist.

Parameters:
  • json_array – String of a JSON array
  • index – index
Return type:

text

Example:
select json_array_get('[100, 200, 300]', 0);
> 100

select json_array_get('[100, 200, 300]', -2);
> 200
json_array_contains(json_array text, value any)

Determine if the given value exists in the JSON array.

Parameters:
  • json_array – String of a JSON array
  • value – value of any type
Return type:

text

Example:
select json_array_contains('[100, 200, 300]', 100);
> t
json_array_length(json_array text)

Returns the length of json array.

Parameters:json_array – String of a JSON array
Return type:int8
Example:
select json_array_length('[100, 200, 300]');
> 3