feat(clickhouse): support PARTITION BY after ORDER BY in CREATE TABLE

ClickHouse DDL allows PARTITION BY to appear after ORDER BY, which
differs from standard SQL ordering. This change makes the parser
accept both orderings when using the ClickHouseDialect or GenericDialect.

Fixes a parse failure for production ClickHouse CREATE TABLE statements
like: CREATE TABLE t (...) ENGINE = MergeTree() ORDER BY (...) PARTITION BY expr

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: 2 people

src/parser/mod.rs

@@ -8564,6 +8564,17 @@ impl<'a> Parser<'a> {
             None
         };
 
+        // ClickHouse allows PARTITION BY after ORDER BY
+        // https://clickhouse.com/docs/en/sql-reference/statements/create/table#partition-by
+        let partition_by = if create_table_config.partition_by.is_none()
+            && dialect_of!(self is ClickHouseDialect | GenericDialect)
+            && self.parse_keywords(&[Keyword::PARTITION, Keyword::BY])
+        {
+            Some(Box::new(self.parse_expr()?))
+        } else {
+            create_table_config.partition_by
+        };
+
         let on_commit = if self.parse_keywords(&[Keyword::ON, Keyword::COMMIT]) {
             Some(self.parse_create_table_on_commit()?)
         } else {
@@ -8634,7 +8645,7 @@ impl<'a> Parser<'a> {
             .on_commit(on_commit)
             .on_cluster(on_cluster)
             .clustered_by(clustered_by)
-            .partition_by(create_table_config.partition_by)
+            .partition_by(partition_by)
             .cluster_by(create_table_config.cluster_by)
             .inherits(create_table_config.inherits)
             .partition_of(partition_of)

tests/sqlparser_clickhouse.rs

@@ -233,6 +233,28 @@ fn parse_create_table() {
     );
 }
 
+#[test]
+fn parse_create_table_partition_by_after_order_by() {
+    // ClickHouse DDL places PARTITION BY after ORDER BY.
+    // MergeTree() is canonicalized to MergeTree and type names are uppercased.
+    clickhouse().one_statement_parses_to(
+        concat!(
+            "CREATE TABLE IF NOT EXISTS \"MyTable\" (`col1` Int64, `col2` Int32) ",
+            "ENGINE = MergeTree() ",
+            "PRIMARY KEY (toDate(toDateTime(`col2`)), `col1`, `col2`) ",
+            "ORDER BY (toDate(toDateTime(`col2`)), `col1`, `col2`) ",
+            "PARTITION BY col1 % 64"
+        ),
+        concat!(
+            "CREATE TABLE IF NOT EXISTS \"MyTable\" (`col1` INT64, `col2` Int32) ",
+            "ENGINE = MergeTree ",
+            "PRIMARY KEY (toDate(toDateTime(`col2`)), `col1`, `col2`) ",
+            "ORDER BY (toDate(toDateTime(`col2`)), `col1`, `col2`) ",
+            "PARTITION BY col1 % 64"
+        ),
+    );
+}
+
 #[test]
 fn parse_insert_into_function() {
     clickhouse().verified_stmt(r#"INSERT INTO TABLE FUNCTION remote('localhost', default.simple_table) VALUES (100, 'inserted via remote()')"#);