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Greetings, SQL enthusiasts! Today, we will delve into the world of MySQL, focusing specifically on JSON_QUERY and JSON_TABLE functions. With the rise of structured and unstructured data, JSON has become a widely-used data format in various applications. MySQL, being one of the most popular database systems, offers robust functions to deal with JSON data.

The JSON_QUERY function in MySQL extracts an object or an array from a JSON string. It is handy when you need to retrieve a complete JSON object or array from a larger JSON document. Let's take an example of a JSON field that holds product information, and we want to extract the specifications array.

-- MySQL code
SELECT JSON_QUERY(product_info, '$.specifications') AS product_specifications
FROM products;

In the above code, JSON_QUERY extracts the 'specifications' array from the 'product_info' JSON field. This function is particularly useful when dealing with complex JSON structures.

Next, let's talk about JSON_TABLE. This MySQL function is a powerful tool that enables you to convert JSON data into tabular format, making it easier to work with. For instance, assume we have a JSON field 'sales_data' with multiple objects representing sales transactions, and we want to convert this JSON data into a table.

-- MySQL code
SELECT *
FROM JSON_TABLE(sales_data, '$[*]'
COLUMNS(
date DATE PATH '$.date',
product VARCHAR(50) PATH '$.product',
quantity INT PATH '$.quantity',
price DECIMAL(10,2) PATH '$.price'
)) AS sales_table;

In the above code, JSON_TABLE transforms the 'sales_data' JSON field into a table with columns 'date', 'product', 'quantity', and 'price'.

But what about when we are dealing with complex databases systems such as SQL Server 2022, Azure SQL or even Delta Lake on Databricks? Microsoft introduced a similar function in SQL Server 2022 called OPENJSON. Moreover, with Microsoft Fabric, we can seamlessly integrate these functions across hybrid databases. If you are using Azure SQL, you can take advantage of Azure's built-in JSON functions.

-- T-SQL code on SQL Server 2022
SELECT *
FROM OPENJSON(@json)
WITH (
date DATE '$.date',
product VARCHAR(50) '$.product',
quantity INT '$.quantity',
price DECIMAL(10,2) '$.price'
);

In the future, with the rise of AI and ML applications, we can expect to see advanced JSON functions powered by OpenAI interfacing with SQL. This will give us even more powerful tools to work with JSON data in SQL. Stay tuned and continue to explore the fascinating world of SQL!