##  json_valid

##  Description
The `json_valid` function is used to verify whether a given string conforms to JSON format specifications. It is important to note that some strings (such as `'1'`) represent valid JSON numbers, but they do not directly meet the JSON format requirements as strings. This function ensures that the string is a valid JSON object or array.

## Parameter Description
- `str`: The string to be validated.

## Return Value
Returns a boolean value indicating whether the input string is in valid JSON format.

- `true`: The input string is in valid JSON format.
- `false`: The input string is not in valid JSON format.

## Usage Example
The following example demonstrates how to use the `json_valid` function to determine whether different strings conform to JSON format.

<Notes>
```sql
-- Valid JSON number
SELECT json_valid('1') AS t;

-- Valid JSON object
SELECT json_valid('{}') AS t;

-- Valid JSON array
SELECT json_valid('[]') AS t;

-- Valid JSON object with key-value pair
SELECT json_valid('{"a": 1}') AS t;

-- Invalid JSON format (empty key name)
SELECT json_valid('{[]}') AS f;

-- Valid JSON array containing an object
SELECT json_valid('[{}]') AS t;

-- String represents a valid JSON number, but as a string does not meet JSON format requirements
SELECT json_valid('"1"') AS f;
```
## Result Interpretation
- `true` indicates that the input string is a valid JSON format.
- `false` indicates that the input string is not a valid JSON format.

Through the above example, you can understand how to use the `json_valid` function to verify whether various strings meet the JSON format requirements. This is very useful when handling JSON data, as it ensures the accuracy and validity of the data.