seve-martinez opened a new pull request, #1566:
URL: https://github.com/apache/datafusion-sqlparser-rs/pull/1566
Snowflake, Databricks, Postgres, and others all support some from of table
sampling.
This commonly takes on the form
```sql
SELECT ...
FROM ...
{ SAMPLE | TABLESAMPLE } [ samplingMethod ]
```
where
```console
samplingMethod ::= { { BERNOULLI | ROW } ( { <probability> | <num> ROWS } ) |
{ SYSTEM | BLOCK } ( <probability> ) [ { REPEATABLE |
SEED } ( <seed> ) ] }
```
Different dialects support one, the other, or both sample keywords and only
some of the methods. The current PR follows the snowflake paradigm.
## Outstanding questions
- [ ] This method is not currently called anywhere. Review of the `Parser`
code would make me think it should be part of the `parse_table_factor()` logic
since it always trails a relation. However this would then require each variant
of `TableFactor` that supports `SAMPLE` to have a placeholder for it. Is that
the right approach?
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