SQLite: Support ON and USING after a comma join

src/dialect/generic.rs

@@ -173,6 +173,10 @@ impl Dialect for GenericDialect {
         true
     }
 
+    fn supports_comma_join_constraint(&self) -> bool {
+        true
+    }
+
     fn supports_comment_on(&self) -> bool {
         true
     }

src/dialect/mod.rs

@@ -445,6 +445,14 @@ pub trait Dialect: Debug + Any {
         false
     }
 
+    /// Returns true if the dialect supports `ON`/`USING` after a comma-joined table,
+    /// e.g. `SELECT * FROM t, u ON t.a = u.a`.
+    ///
+    /// [SQLite](https://www.sqlite.org/syntax/join-clause.html)
+    fn supports_comma_join_constraint(&self) -> bool {
+        false
+    }
+
     /// Returns true if the dialect supports CONNECT BY.
     fn supports_connect_by(&self) -> bool {
         false

src/dialect/sqlite.rs

@@ -146,4 +146,8 @@ impl Dialect for SQLiteDialect {
     fn supports_parens_around_table_factor(&self) -> bool {
         true
     }
+
+    fn supports_comma_join_constraint(&self) -> bool {
+        true
+    }
 }

src/parser/mod.rs

@@ -5086,13 +5086,37 @@ impl<'a> Parser<'a> {
 
     /// Parse a list of [TableWithJoins]
     fn parse_table_with_joins(&mut self) -> Result<Vec<TableWithJoins>, ParserError> {
-        let trailing_commas = self.dialect.supports_from_trailing_commas();
+        let dialect = self.dialect;
+        let trailing_commas = dialect.supports_from_trailing_commas();
+        let mut tables: Vec<TableWithJoins> = vec![];
 
         self.parse_comma_separated_with_trailing_commas(
-            Parser::parse_table_and_joins,
+            |parser| {
+                let table = parser.parse_table_and_joins()?;
+                match tables.last_mut() {
+                    Some(previous)
+                        if dialect.supports_comma_join_constraint()
+                            && table.joins.is_empty()
+                            && parser
+                                .peek_one_of_keywords(&[Keyword::ON, Keyword::USING])
+                                .is_some() =>
+                    {
+                        let constraint = parser.parse_join_constraint(false)?;
+                        previous.joins.push(Join {
+                            relation: table.relation,
+                            global: false,
+                            join_operator: JoinOperator::Join(constraint),
+                        });
+                        previous.joins.extend(parser.parse_joins()?);
+                    }
+                    _ => tables.push(table),
+                }
+                Ok(())
+            },
             trailing_commas,
-            |kw, parser| !self.dialect.is_table_factor(kw, parser),
-        )
+            |kw, parser| !dialect.is_table_factor(kw, parser),
+        )?;
+        Ok(tables)
     }
 
     /// Parse the comma of a comma-separated syntax element.

tests/sqlparser_sqlite.rs

@@ -1142,6 +1142,44 @@ fn parse_parenthesized_table_factor() {
     );
 }
 
+#[test]
+fn parse_comma_join_constraint() {
+    let dialects = all_dialects_where(|d| d.supports_comma_join_constraint());
+    for (sql, canonical) in [
+        (
+            "SELECT * FROM t, u ON t.a = u.a",
+            "SELECT * FROM t JOIN u ON t.a = u.a",
+        ),
+        (
+            "SELECT * FROM t, u USING (a)",
+            "SELECT * FROM t JOIN u USING(a)",
+        ),
+        (
+            "SELECT * FROM t, u ON t.a = u.a, v ON v.a = u.a",
+            "SELECT * FROM t JOIN u ON t.a = u.a JOIN v ON v.a = u.a",
+        ),
+        (
+            "SELECT * FROM t, u ON t.a = u.a JOIN v ON v.a = u.a",
+            "SELECT * FROM t JOIN u ON t.a = u.a JOIN v ON v.a = u.a",
+        ),
+        (
+            "UPDATE t SET a = 1 FROM u, v ON u.a = v.a",
+            "UPDATE t SET a = 1 FROM u JOIN v ON u.a = v.a",
+        ),
+    ] {
+        dialects.one_statement_parses_to(sql, canonical);
+    }
+    dialects.verified_stmt("SELECT * FROM t, u");
+
+    assert_eq!(
+        all_dialects_where(|d| !d.supports_comma_join_constraint())
+            .parse_sql_statements("SELECT * FROM t, u ON t.a = u.a"),
+        Err(ParserError::ParserError(
+            "Expected: end of statement, found: ON".to_string()
+        ))
+    );
+}
+
 fn sqlite() -> TestedDialects {
     TestedDialects::new(vec![Box::new(SQLiteDialect {})])
 }