raminqaf commented on code in PR #29617:
URL: https://github.com/apache/flink/pull/29617#discussion_r4401624817
##########
docs/content.zh/docs/sql/functions/built-in-functions.md:
##########
@@ -233,6 +233,35 @@ A document fails to parse if it:
In all of these cases, `TRY_PARSE_XML` returns `NULL`.
+#### Variant paths
+
+`VARIANT_GET` and `TRY_VARIANT_GET` take a path that names one place in a
Variant. A path starts
+with `$`, the whole value, followed by steps: `.name`, `['name']` or
`["name"]` for a field, and
+`[n]` for an array element. For example, on
+`PARSE_JSON('{"user": {"name": "ada"}, "items": [{"qty": 2}]}')`:
+
+| Path | Points at |
+|---------------------|------------------------------------|
+| `$` | the whole value |
+| `$.user.name` | `"ada"` |
+| `$['user']["name"]` | `"ada"` |
+| `$.items[0].qty` | `2` |
+| `$.items[1]` | nothing, the index is past the end |
+| `$.user[0]` | nothing, `user` is not an array |
+
+- Array indices start at 0, as in `JSON_VALUE`, while `variant[INT]` starts at
1. So `$.items[0]`
+ and `v['items'][1]` are the same element.
+- Use brackets for a name with whitespace or one of the characters `. [ ] ( )
* ' " \`, for example
+ `$['first name']`. Inside the quotes, `\\`, `\'` and `\"` stand for a
backslash and a quote.
Review Comment:
Yes. `$["first name"]` works like `$['first name']`, and inside double
quotes `\"` escapes a double quote. The bullet now says brackets take single or
double quotes and shows both forms.
##########
docs/content.zh/docs/sql/functions/built-in-functions.md:
##########
@@ -233,6 +233,35 @@ A document fails to parse if it:
In all of these cases, `TRY_PARSE_XML` returns `NULL`.
+#### Variant paths
+
+`VARIANT_GET` and `TRY_VARIANT_GET` take a path that names one place in a
Variant. A path starts
+with `$`, the whole value, followed by steps: `.name`, `['name']` or
`["name"]` for a field, and
+`[n]` for an array element. For example, on
+`PARSE_JSON('{"user": {"name": "ada"}, "items": [{"qty": 2}]}')`:
+
+| Path | Points at |
+|---------------------|------------------------------------|
+| `$` | the whole value |
+| `$.user.name` | `"ada"` |
+| `$['user']["name"]` | `"ada"` |
+| `$.items[0].qty` | `2` |
+| `$.items[1]` | nothing, the index is past the end |
+| `$.user[0]` | nothing, `user` is not an array |
+
+- Array indices start at 0, as in `JSON_VALUE`, while `variant[INT]` starts at
1. So `$.items[0]`
+ and `v['items'][1]` are the same element.
+- Use brackets for a name with whitespace or one of the characters `. [ ] ( )
* ' " \`, for example
+ `$['first name']`. Inside the quotes, `\\`, `\'` and `\"` stand for a
backslash and a quote.
+- Wildcards, filters, slices, negative indices and the `lax` and `strict`
modes are not supported,
+ so a path always names one place.
+- Trailing spaces are ignored, so a path read from a `CHAR(n)` column works.
Review Comment:
done
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