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Overview

JSON_EXTRACT_PATH() function extracts JSON nested value from a specified path.

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Syntax

The syntax of the JSON_EXTRACT_PATH() function can be seen below. 
JSON_EXTRACT_PATH(from_json JSON, path TEXT[])
  • from_json: the JSON value from which to extract.
  • path: the path to extract.

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Another Option

Besides the syntax above, Oxla provides and supports the use of operators in queries. See the syntax below: 
SELECT 'from_json'::JSON -> 'path';
  • from_json: the JSON value from which to extract.
  • ::JSON: a symbol that casts the text literal to a JSON type.
  • path: key of the field that we want to extract.

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Examples

These examples display how JSON_EXTRACT_PATH() extracts the “oxla” JSON sub-object from the specified path.
  1. Use the below query:
SELECT JSON_EXTRACT_PATH('{"f2":{"f3":1},"f4":{"f5":99,"f6":"oxla"}}', 'f4', 'f6');
or 
SELECT '{"f2":{"f3":1},"f4":{"f5":99,"f6":"oxla"}}'::JSON -> 'f4' -> 'f6';
The query above will return the following result. 
+---------+
| f       |
+---------+
| "oxla"  |
+---------+
  1. Run the query below:
SELECT
    JSON_EXTRACT_PATH('{"a": 1, "b": {"x": "subtract", "y": "plus"}}', 'b', 'x') AS "bx",
    JSON_EXTRACT_PATH('{"a": 1, "b": {"x": "multiply", "y": "divide"}}', 'b', 'y') AS "by";
You will get the following output: 
+---------------+-------------+
| bx            | by          |
+---------------+-------------+
| "subtract"    | "divide"    |
+---------------+-------------+