[jira] [Updated] (CALCITE-2808) Add the JSON_LENGTH function

["Forward Xu (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CALCITE-2808?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Forward Xu updated CALCITE-2808:
--------------------------------
    Description: 
```
 JSON_LENGTH(**json_doc**[, *path*])
 ```

Returns the length of a JSON document, or, if a *path* argument is given, the length of the value within the document identified by the path. Returns `NULL` if any argument is `NULL` or the *path* argument does not identify a value in the document. An error occurs if the *json_doc* argument is not a valid JSON document or the *path* argument is not a valid path expression or contains a {**} or }}**{{`*` wildcard.

The length of a document is determined as follows:
 - The length of a scalar is 1.

 - The length of an array is the number of array elements.

 - The length of an object is the number of object members.

 - The length does not count the length of nested arrays or objects.

Example Sql:
{code:java}
// code placeholder
SELECT JSON_LENGTH(v, 'lax $') AS c1
,JSON_LENGTH(v, 'lax $.a') AS c2
,JSON_LENGTH(v, 'strict $.a[0]') AS c3
,JSON_LENGTH(v, 'strict $.a[1]') AS c4
FROM (VALUES ('{"a": [10, true]}')) AS t(v)
LIMIT 10;{code}
Result:
||c1||c2||c3||c4||
|1|2|1|1|

 

  was:
```
JSON_LENGTH(**json_doc**[, *path*])
```

Returns the length of a JSON document, or, if a *path* argument is given, the length of the value within the document identified by the path. Returns `NULL` if any argument is `NULL` or the *path* argument does not identify a value in the document. An error occurs if the *json_doc* argument is not a valid JSON document or the *path* argument is not a valid path expression or contains a \{**} or }}**{{`*` wildcard.

The length of a document is determined as follows:

- The length of a scalar is 1.

- The length of an array is the number of array elements.

- The length of an object is the number of object members.

- The length does not count the length of nested arrays or objects.

Example Sql:

```sql
SELECT JSON_LENGTH(v, 'lax $' ERROR ON ERROR) AS c1
,JSON_LENGTH(v, 'lax $.a' ERROR ON ERROR) AS c2
,JSON_LENGTH(v, 'strict $.a[0]' ERROR ON ERROR) AS c3
,JSON_LENGTH(v, 'strict $.a[1]' ERROR ON ERROR) AS c4
FROM (VALUES ('\{"a": [10, true]}')) AS t(v)
limit 10;
```

Result:

| c1 | c2 | c3 | c4 |
| ---- | ---- | ---- | ---- |
| 1 | 2 | 1 | 1 |

 


> Add the JSON_LENGTH function 
> -----------------------------
>
>                 Key: CALCITE-2808
>                 URL: https://issues.apache.org/jira/browse/CALCITE-2808
>             Project: Calcite
>          Issue Type: Sub-task
>            Reporter: Forward Xu
>            Assignee: Forward Xu
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 1h 10m
>  Remaining Estimate: 0h
>
> ```
>  JSON_LENGTH(**json_doc**[, *path*])
>  ```
> Returns the length of a JSON document, or, if a *path* argument is given, the length of the value within the document identified by the path. Returns `NULL` if any argument is `NULL` or the *path* argument does not identify a value in the document. An error occurs if the *json_doc* argument is not a valid JSON document or the *path* argument is not a valid path expression or contains a {**} or }}**{{`*` wildcard.
> The length of a document is determined as follows:
>  - The length of a scalar is 1.
>  - The length of an array is the number of array elements.
>  - The length of an object is the number of object members.
>  - The length does not count the length of nested arrays or objects.
> Example Sql:
> {code:java}
> // code placeholder
> SELECT JSON_LENGTH(v, 'lax $') AS c1
> ,JSON_LENGTH(v, 'lax $.a') AS c2
> ,JSON_LENGTH(v, 'strict $.a[0]') AS c3
> ,JSON_LENGTH(v, 'strict $.a[1]') AS c4
> FROM (VALUES ('{"a": [10, true]}')) AS t(v)
> LIMIT 10;{code}
> Result:
> ||c1||c2||c3||c4||
> |1|2|1|1|
>  



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