How can write queries in MySQL that can parse JSON data in a column?

Question

I have a table in MySQL that has a column that store JSON objects. How can I easily run queries that can have some of the JSON fields in the WHERE clause?

EX: Wi

Answer 1

You could use json_extract (5.7 up). https://dev.mysql.com/doc/refman/5.7/en/json-search-functions.html#function_json-extract

SELECT user_id, json_data
FROM articles 
WHERE json_extract(json_data, '$.title') LIKE '%CPU%';

Answer 2

I ended up solving in this way: https://github.com/ChrisCinelli/mysql_json with a UDF. I detailed how to compile it and install it in the README. It works for me on Ubuntu 12.04.5 on gcc version 4.6.3 with MySQL 5.5

You will be able to run:

SELECT json_get('{"a":1}', 'a')       => 1
SELECT json_get('{"a":1}', 'b')       => NULL
SELECT json_get('[1,2,3]', 2)         => 3
SELECT json_get('{"a":[2]}', 'a', 0)  => 2

#Also:

SELECT json_get('{"a":{"b":2}}', 'a') => object
SELECT json_get('{"a":[1,2,3]}', 'a') => array

# Verify if it is a valid JSON:

SELECT ISNULL(json_get('{"a":1}'));   => 0  # Valid
SELECT ISNULL(json_get('{"a":1'));    => 1  # Invalid

# Create an example table:

CREATE TABLE `message` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `data` text,
  PRIMARY KEY (`id`)
);
INSERT INTO message (id,data) VALUES(1,'{"from":"chris","title":"Awesome Article","body":"Lorem ipsum dolor sit amet, consectetur adipiscing elit."}');
INSERT INTO message (id,data) VALUES(2,'{"from":"loren","title":"Another Article","body":"Lorem ipsum dolor sit amet, consectetur adipiscing elit."}');
INSERT INTO message (id,data) VALUES(3,'{"from":"jason","title":"How to run a query","body":"Lorem ipsum dolor sit amet, consectetur adipiscing elit."}');

# Run queries on JSON values:

SELECT json_get(data,'title') FROM message WHERE id=2;
SELECT id,data FROM message WHERE json_get(data,'from')='chris';
SELECT id,data FROM message WHERE json_get(data,'title') LIKE '%Article%';

Answer 3

Try the following query and see if it fits your needs:

SELECT user_id, json_data
FROM articles
WHERE common_schema.extract_json_value(json_data,'title')
LIKE "%CPU%"

This will only work on MySQL version 5.1 or newer.