Database Management Systems
In MariaDB, JSON_KEYS() is a built-in function that returns an array of the top-level keys from a JSON document. If a path is provided, it returns the top-level keys from that path.
It excludes keys from nested sub-objects in the specified level.
Also, if the selected object is empty, an empty array is returned.
Continue readingIn MariaDB, JSON_SET() is a built-in function that updates or inserts data into a JSON document and returns the result.
JSON_SET() can update and insert data, whereas JSON_INSERT() can only insert data, and JSON_REPLACE() can only update data.
In MariaDB, JSON_REPLACE() is a built-in function that replaces existing values in a JSON document and returns the result.
In MariaDB, JSON_INSERT() is a built-in function that inserts data into a JSON document, and returns the result.
If you use SQL Server Management Studio (SSMS) or some other GUI to manage your databases, you might be used to backing up and restoring databases using “point and click”.
Usually this involves right-clicking on the database and selecting Restore or similar, then following the prompts (for example, when restoring a database in Azure Data Studio).
But if you ever need to do it with T-SQL, you can use the RESTORE DATABASE statement.
In MariaDB, JSON_DEPTH() is a built-in function that allows you to check the depth of a JSON document.
It accepts the JSON document as an argument, and returns the maximum depth of the document.
Continue readingIn MariaDB, JSON_EXISTS() is a built-in function that allows you to check whether a value exists at a specified path in the JSON document.
It accepts the JSON document as an argument, and returns 1 if the path is found, and 0 if it’s not.
The MariaDB documentation states that the function “determines whether a specified JSON value exists in the given data”. However, the function doesn’t actually appear to check for a given value. It’s probably more accurate to say that it determines whether a specified path exists, or that a value exists at the specified path.
For checking that the actual value exists, you can use the JSON_CONTAINS() function.
Here are two ways to return the short month name from a date in MariaDB.
Continue readingIn MariaDB, JSON_QUERY() is a built-in function that returns an object or array from a JSON document, based on the path provided.
It’s similar to the JSON_VALUE() function, except that it returns an object or array instead of a scalar (JSON_VALUE() returns a scalar).
In MariaDB, JSON_VALUE() is a built-in function that returns a scalar value from a JSON document. More specifically, it returns the scalar specified by the path provided.