How the JSON_QUOTE() function works in Mariadb?

The JSON_QUOTE() function is a built-in function in Mariadb that allows you to quote a string as a JSON value. It can be useful when you want to construct a JSON value from a string that may contain special characters or invalid JSON syntax.

Syntax

The syntax of the JSON_QUOTE() function is as follows:

JSON_QUOTE(string)

The function takes one argument, as follows:

• string: This is the string to quote as a JSON value. It can be any string or a column that contains strings.

The function returns a new string that is quoted as a JSON value.

Examples

Example 1: Quoting a simple string

In this example, we use the JSON_QUOTE() function to quote a simple string as a JSON value.

SELECT JSON_QUOTE(
  'Hello, world!'
) AS quoted_string;

The output is:

+-----------------+
| quoted_string   |
+-----------------+
| "Hello, world!" |
+-----------------+

As you can see, the function returns a string that is enclosed in double quotes, as a valid JSON value.

Example 2: Quoting a string with special characters

In this example, we use the JSON_QUOTE() function to quote a string that contains special characters as a JSON value.

SELECT JSON_QUOTE(
  'This is a "quoted" string with \n a new line and a \t tab'
) AS quoted_string;

The output is:

+---------------------------------------------------------------+
| quoted_string                                                 |
+---------------------------------------------------------------+
| "This is a \"quoted\" string with \n a new line and a \t tab" |
+---------------------------------------------------------------+

As you can see, the function returns a string that is enclosed in double quotes, and escapes the double quotes, the new line, and the tab characters with backslashes, as a valid JSON value.

Example 3: Quoting a string with invalid JSON syntax

In this example, we use the JSON_QUOTE() function to quote a string that has invalid JSON syntax as a JSON value.

SELECT JSON_QUOTE(
  '{a: b, c: d}'
) AS quoted_string;

The output is:

+----------------+
| quoted_string  |
+----------------+
| "{a: b, c: d}" |
+----------------+

As you can see, the function returns a string that is enclosed in double quotes, and does not attempt to parse or validate the JSON syntax, as a valid JSON value.

Related Functions

There are some other functions in Mariadb that are related to the JSON_QUOTE() function. Here are some of them:

• JSON_UNQUOTE() function: This function does the opposite of the JSON_QUOTE() function. It unquotes a JSON value and returns a string. It takes a JSON value as an argument, and returns a string that is unquoted and unescaped. For example, JSON_UNQUOTE('"Hello, world!"') returns Hello, world!.
• JSON_VALID() function: This function checks whether a string is a valid JSON document. It takes a string as an argument, and returns 1 if the string is a valid JSON document, or 0 otherwise. For example, JSON_VALID('{"a": "b", "c": "d"}') returns 1.
• JSON_TYPE() function: This function returns the type of a JSON value. It takes a JSON value as an argument, and returns a string that indicates the type of the JSON value. For example, JSON_TYPE('"Hello, world!"') returns STRING.

Conclusion

The JSON_QUOTE() function is a useful function in Mariadb that allows you to quote a string as a JSON value. It can handle different types of strings, such as simple strings, strings with special characters, or strings with invalid JSON syntax. It returns a new string that is quoted as a JSON value. There are also some other functions that are related to the JSON_QUOTE() function, such as JSON_UNQUOTE(), JSON_VALID(), and JSON_TYPE(). You can use these functions to manipulate JSON data in different ways.