Database Management Systems
In MySQL, the JSON_CONTAINS() function tests whether or not a specified value is found in the given JSON document or, optionally, at the specified path within the document.
If the value is found, JSON_CONTAINS() returns 1, otherwise it returns 0.
When using MySQL, you can use the JSON_VALID() function to test whether or not a string expression contains valid JSON.
If the expression contains valid JSON, JSON_VALID() returns 1, otherwise it returns 0.
In MySQL, the JSON_UNQUOTE() function “unquotes” a JSON document and returns the result as a utf8mb4 string.
You provide the JSON document as an argument, and the function will do the rest.
In MySQL, there are a number of functions to help you work with JSON documents. These include the JSON_SET(), JSON_INSERT(), and JSON_REPLACE() functions.
These three functions are related, yet they do differ slightly.
In MySQL, the JSON_SET() function inserts or updates values in a JSON document and returns the result.
You provide the JSON document as the first argument, followed by the path to insert into, followed by the value to insert. You can provide multiple path/value pairs if you need to update multiple values.
In MySQL, the JSON_REPLACE() function replaces values in a JSON document and returns the result.
You provide the JSON document as the first argument, followed by the path to replace data at, followed with the value to replace the existing value with.
You can replace data at multiple places in the document if required. To do this, simply provide multiple path/value pairs as required.
In MySQL, the JSON_REMOVE() function removes data from a JSON document and returns the result.
You provide the JSON document as the first argument, followed by the path to remove data from. You can provide multiple paths if required.
MySQLÂ includes a number of functions for working with JSON documents. Among these are the JSON_MERGE_PATCH() and JSON_MERGE_PRESERVE() functions.
Both of these functions merge two or more JSON documents and return the result. However, there are certain cases where these functions will return a different result. You need to be aware of this before including them in any of your queries.
In MySQL, the JSON_MERGE_PRESERVE() function merges two or more JSON documents and returns the result.
You provide the JSON documents as arguments.
This function was added in MySQL 8.0.3 as a synonym for JSON_MERGE(), however, the JSON_MERGE() function is now deprecated, and is subject to removal in a future release of MySQL.
In MySQL, the JSON_MERGE_PATCH() function performs an RFC 7396 compliant merge of two or more JSON documents, without preserving members having duplicate keys.
You provide the JSON documents as arguments.