[
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:
```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 |
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:
SELECT JSON_LENGTH(v, 'lax $' ERROR ON ERROR
) AS c1
,JSON_LENGTH(v, 'lax $.b' ERROR ON ERROR) AS c2
,JSON_LENGTH(v, 'strict $.a[0]' with wapper) AS c3
,JSON_LENGTH(v, 'strict $.a[1]' with wapper) AS c4
FROM (VALUES ('
{"a": [10, true],"b": "[10, true]"}
')) AS t(v)
limit 10;
Result:
c1 c2 c3 c4
== == == ==
2 1 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: 0.5h
> 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:
> ```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 |
>
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