BigQuery: Support trailing commas in column definitions list (#1682)

Author: iffyio

src/dialect/bigquery.rs

@@ -31,6 +31,11 @@ impl Dialect for BigQueryDialect {
         true
     }
 
+    /// See <https://cloud.google.com/bigquery/docs/reference/standard-sql/data-definition-language#create_table_statement>
+    fn supports_column_definition_trailing_commas(&self) -> bool {
+        true
+    }
+
     fn is_identifier_start(&self, ch: char) -> bool {
         ch.is_ascii_lowercase() || ch.is_ascii_uppercase() || ch == '_'
     }

src/dialect/mod.rs

@@ -405,11 +405,18 @@ pub trait Dialect: Debug + Any {
     }
 
     /// Returns true if the dialect supports trailing commas in the `FROM` clause of a `SELECT` statement.
-    /// /// Example: `SELECT 1 FROM T, U, LIMIT 1`
+    /// Example: `SELECT 1 FROM T, U, LIMIT 1`
     fn supports_from_trailing_commas(&self) -> bool {
         false
     }
 
+    /// Returns true if the dialect supports trailing commas in the
+    /// column definitions list of a `CREATE` statement.
+    /// Example: `CREATE TABLE T (x INT, y TEXT,)`
+    fn supports_column_definition_trailing_commas(&self) -> bool {
+        false
+    }
+
     /// Returns true if the dialect supports double dot notation for object names
     ///
     /// Example

src/parser/mod.rs

@@ -6718,7 +6718,11 @@ impl<'a> Parser<'a> {
                 return self.expected("',' or ')' after column definition", self.peek_token());
             };
 
-            if rparen && (!comma || self.options.trailing_commas) {
+            if rparen
+                && (!comma
+                    || self.dialect.supports_column_definition_trailing_commas()
+                    || self.options.trailing_commas)
+            {
                 let _ = self.consume_token(&Token::RParen);
                 break;
             }
@@ -9298,7 +9302,11 @@ impl<'a> Parser<'a> {
                 self.next_token();
                 Ok(vec![])
             } else {
-                let cols = self.parse_comma_separated(Parser::parse_view_column)?;
+                let cols = self.parse_comma_separated_with_trailing_commas(
+                    Parser::parse_view_column,
+                    self.dialect.supports_column_definition_trailing_commas(),
+                    None,
+                )?;
                 self.expect_token(&Token::RParen)?;
                 Ok(cols)
             }

tests/sqlparser_common.rs

@@ -10189,15 +10189,19 @@ fn parse_trailing_comma() {
             "Expected: column name or constraint definition, found: )".to_string()
         )
     );
+
+    let unsupported_dialects = all_dialects_where(|d| !d.supports_trailing_commas());
+    assert_eq!(
+        unsupported_dialects
+            .parse_sql_statements("SELECT * FROM track ORDER BY milliseconds,")
+            .unwrap_err(),
+        ParserError::ParserError("Expected: an expression, found: EOF".to_string())
+    );
 }
 
 #[test]
 fn parse_projection_trailing_comma() {
-    // Some dialects allow trailing commas only in the projection
-    let trailing_commas = TestedDialects::new(vec![
-        Box::new(SnowflakeDialect {}),
-        Box::new(BigQueryDialect {}),
-    ]);
+    let trailing_commas = all_dialects_where(|d| d.supports_projection_trailing_commas());
 
     trailing_commas.one_statement_parses_to(
         "SELECT album_id, name, FROM track",
@@ -10210,20 +10214,14 @@ fn parse_projection_trailing_comma() {
 
     trailing_commas.verified_stmt("SELECT DISTINCT ON (album_id) name FROM track");
 
+    let unsupported_dialects = all_dialects_where(|d| {
+        !d.supports_projection_trailing_commas() && !d.supports_trailing_commas()
+    });
     assert_eq!(
-        trailing_commas
-            .parse_sql_statements("SELECT * FROM track ORDER BY milliseconds,")
+        unsupported_dialects
+            .parse_sql_statements("SELECT album_id, name, FROM track")
             .unwrap_err(),
-        ParserError::ParserError("Expected: an expression, found: EOF".to_string())
-    );
-
-    assert_eq!(
-        trailing_commas
-            .parse_sql_statements("CREATE TABLE employees (name text, age int,)")
-            .unwrap_err(),
-        ParserError::ParserError(
-            "Expected: column name or constraint definition, found: )".to_string()
-        ),
+        ParserError::ParserError("Expected an expression, found: FROM".to_string())
     );
 }
 
@@ -13061,6 +13059,33 @@ fn parse_overlaps() {
     verified_stmt("SELECT (DATE '2016-01-10', DATE '2016-02-01') OVERLAPS (DATE '2016-01-20', DATE '2016-02-10')");
 }
 
+#[test]
+fn parse_column_definition_trailing_commas() {
+    let dialects = all_dialects_where(|d| d.supports_column_definition_trailing_commas());
+
+    dialects.one_statement_parses_to("CREATE TABLE T (x INT64,)", "CREATE TABLE T (x INT64)");
+    dialects.one_statement_parses_to(
+        "CREATE TABLE T (x INT64, y INT64, )",
+        "CREATE TABLE T (x INT64, y INT64)",
+    );
+    dialects.one_statement_parses_to(
+        "CREATE VIEW T (x, y, ) AS SELECT 1",
+        "CREATE VIEW T (x, y) AS SELECT 1",
+    );
+
+    let unsupported_dialects = all_dialects_where(|d| {
+        !d.supports_projection_trailing_commas() && !d.supports_trailing_commas()
+    });
+    assert_eq!(
+        unsupported_dialects
+            .parse_sql_statements("CREATE TABLE employees (name text, age int,)")
+            .unwrap_err(),
+        ParserError::ParserError(
+            "Expected: column name or constraint definition, found: )".to_string()
+        ),
+    );
+}
+
 #[test]
 fn test_trailing_commas_in_from() {
     let dialects = all_dialects_where(|d| d.supports_from_trailing_commas());