Support TABLESAMPLE RESERVOIR

fuzz/fuzz_seeds/bigquery_tablesample_reservoir.sql

@@ -0,0 +1 @@
+SELECT * FROM t TABLESAMPLE RESERVOIR (100 ROWS) REPEATABLE (10)

src/ast/query.rs

@@ -1883,6 +1883,12 @@ pub enum TableSampleMethod {
     System,
     /// `BLOCK` sampling method.
     Block,
+    /// `RESERVOIR` sampling method.
+    ///
+    /// Picks a fixed number of rows (`n ROWS`) at random, or every row when the input has fewer.
+    ///
+    /// [Spanner](https://cloud.google.com/spanner/docs/reference/standard-sql/query-syntax#tablesample_operator)
+    Reservoir,
 }
 
 impl fmt::Display for TableSampleMethod {
@@ -1892,6 +1898,7 @@ impl fmt::Display for TableSampleMethod {
             TableSampleMethod::Row => write!(f, "ROW"),
             TableSampleMethod::System => write!(f, "SYSTEM"),
             TableSampleMethod::Block => write!(f, "BLOCK"),
+            TableSampleMethod::Reservoir => write!(f, "RESERVOIR"),
         }
     }
 }

src/keywords.rs

@@ -912,6 +912,7 @@ define_keywords!(
     REPLICATE,
     REPLICATION,
     REQUIRE,
+    RESERVOIR,
     RESET,
     RESOLVE,
     RESOURCE,

src/parser/mod.rs

@@ -17941,11 +17941,13 @@ impl<'a> Parser<'a> {
             Keyword::ROW,
             Keyword::SYSTEM,
             Keyword::BLOCK,
+            Keyword::RESERVOIR,
         ]) {
             Some(Keyword::BERNOULLI) => Some(TableSampleMethod::Bernoulli),
             Some(Keyword::ROW) => Some(TableSampleMethod::Row),
             Some(Keyword::SYSTEM) => Some(TableSampleMethod::System),
             Some(Keyword::BLOCK) => Some(TableSampleMethod::Block),
+            Some(Keyword::RESERVOIR) => Some(TableSampleMethod::Reservoir),
             _ => None,
         };
 

tests/sqlparser_common.rs

@@ -17628,6 +17628,14 @@ fn test_table_sample() {
     dialects.verified_stmt("SELECT * FROM tbl AS t TABLESAMPLE BERNOULLI (50)");
     dialects.verified_stmt("SELECT * FROM tbl AS t TABLESAMPLE SYSTEM (50)");
     dialects.verified_stmt("SELECT * FROM tbl AS t TABLESAMPLE SYSTEM (50) REPEATABLE (10)");
+    dialects.verified_stmt("SELECT * FROM tbl AS t TABLESAMPLE RESERVOIR (50 ROWS)");
+
+    assert_eq!(
+        dialects
+            .parse_sql_statements("SELECT * FROM tbl TABLESAMPLE RESERVOIR ()")
+            .unwrap_err(),
+        ParserError::ParserError("Expecting number or byte length e.g. 100M".to_string())
+    );
 }
 
 #[test]