Support Snowflake Update-From-Select

src/keywords.rs

@@ -940,6 +940,7 @@ pub const RESERVED_FOR_TABLE_ALIAS: &[Keyword] = &[
     // Reserved for Snowflake table sample
     Keyword::SAMPLE,
     Keyword::TABLESAMPLE,
+    Keyword::FROM,
 ];
 
 /// Can't be used as a column alias, so that `SELECT <expr> alias`

src/parser/mod.rs

@@ -11679,14 +11679,21 @@ impl<'a> Parser<'a> {
     pub fn parse_update(&mut self) -> Result<Statement, ParserError> {
         let or = self.parse_conflict_clause();
         let table = self.parse_table_and_joins()?;
+        let from_before_set = if self.parse_keyword(Keyword::FROM)
+            && dialect_of!(self is GenericDialect | PostgreSqlDialect | DuckDbDialect | BigQueryDialect | SnowflakeDialect | RedshiftSqlDialect | MsSqlDialect | SQLiteDialect )
+        {
+            Some(self.parse_table_and_joins()?)
+        } else {
+            None
+        };
         self.expect_keyword(Keyword::SET)?;
         let assignments = self.parse_comma_separated(Parser::parse_assignment)?;
         let from = if self.parse_keyword(Keyword::FROM)
             && dialect_of!(self is GenericDialect | PostgreSqlDialect | DuckDbDialect | BigQueryDialect | SnowflakeDialect | RedshiftSqlDialect | MsSqlDialect | SQLiteDialect )
         {
             Some(self.parse_table_and_joins()?)
         } else {
-            None
+            from_before_set
         };
         let selection = if self.parse_keyword(Keyword::WHERE) {
             Some(self.parse_expr()?)

tests/sqlparser_snowflake.rs

@@ -2974,3 +2974,10 @@ fn test_table_sample() {
     snowflake_and_generic().verified_stmt("SELECT id FROM mytable TABLESAMPLE (10) REPEATABLE (1)");
     snowflake_and_generic().verified_stmt("SELECT id FROM mytable TABLESAMPLE (10) SEED (1)");
 }
+
+#[test]
+fn parse_update_from_before_select() {
+    assert!(snowflake()
+    .parse_sql_statements("UPDATE t1 FROM (SELECT name, id FROM t1 GROUP BY id) AS t2 SET name = t2.name WHERE t1.id = t2.id")
+    .is_ok());
+}