Add support of ATTACH/DETACH PARTITION for ClickHouse

See:

- https://clickhouse.com/docs/en/sql-reference/statements/alter/partition#attach-partitionpart
- https://clickhouse.com/docs/en/sql-reference/statements/alter/partition#detach-partitionpart

Author: git-hulk

src/ast/ddl.rs

@@ -72,6 +72,21 @@ pub enum AlterTableOperation {
         if_exists: bool,
         cascade: bool,
     },
+    /// `ATTACH PART|PARTITION <partition_expr>`
+    /// Note: this is a ClickHouse-specific operation, please refer to
+    /// [ClickHouse](https://clickhouse.com/docs/en/sql-reference/statements/alter/partition#detach-partitionpart)
+    AttachPartition {
+        // PART is not a short form of PARTITION, it's a separate keyword
+        // which represents a physical file on disk and partition is a logical entity.
+        partition: Partition,
+    },
+    /// `DETACH PART|PARTITION <partition_expr>`
+    /// Note: this is a ClickHouse-specific operation, please refer to
+    /// [ClickHouse](https://clickhouse.com/docs/en/sql-reference/statements/alter/partition#detach-partitionpart)
+    DetachPartition {
+        // See `AttachPartition` for more details
+        partition: Partition,
+    },
     /// `DROP PRIMARY KEY`
     ///
     /// Note: this is a MySQL-specific operation.
@@ -272,6 +287,12 @@ impl fmt::Display for AlterTableOperation {
                 column_name,
                 if *cascade { " CASCADE" } else { "" }
             ),
+            AlterTableOperation::AttachPartition { partition } => {
+                write!(f, "ATTACH {partition}")
+            }
+            AlterTableOperation::DetachPartition { partition } => {
+                write!(f, "DETACH {partition}")
+            }
             AlterTableOperation::EnableAlwaysRule { name } => {
                 write!(f, "ENABLE ALWAYS RULE {name}")
             }
@@ -1305,6 +1326,9 @@ impl fmt::Display for UserDefinedTypeCompositeAttributeDef {
 pub enum Partition {
     Identifier(Ident),
     Expr(Expr),
+    /// ClickHouse supports PART expr which represents physical partition in disk.
+    /// [ClickHouse](https://clickhouse.com/docs/en/sql-reference/statements/alter/partition#attach-partitionpart)
+    Part(Expr),
     Partitions(Vec<Expr>),
 }
 
@@ -1313,6 +1337,7 @@ impl fmt::Display for Partition {
         match self {
             Partition::Identifier(id) => write!(f, "PARTITION ID {id}"),
             Partition::Expr(expr) => write!(f, "PARTITION {expr}"),
+            Partition::Part(expr) => write!(f, "PART {expr}"),
             Partition::Partitions(partitions) => {
                 write!(f, "PARTITION ({})", display_comma_separated(partitions))
             }

src/keywords.rs

@@ -539,6 +539,7 @@ define_keywords!(
     PARALLEL,
     PARAMETER,
     PARQUET,
+    PART,
     PARTITION,
     PARTITIONED,
     PARTITIONS,

src/parser/mod.rs

@@ -6540,7 +6540,7 @@ impl<'a> Parser<'a> {
         } else if dialect_of!(self is PostgreSqlDialect | GenericDialect)
             && self.parse_keywords(&[Keyword::OWNER, Keyword::TO])
         {
-            let new_owner = match self.parse_one_of_keywords( &[Keyword::CURRENT_USER, Keyword::CURRENT_ROLE, Keyword::SESSION_USER]) {
+            let new_owner = match self.parse_one_of_keywords(&[Keyword::CURRENT_USER, Keyword::CURRENT_ROLE, Keyword::SESSION_USER]) {
                 Some(Keyword::CURRENT_USER) => Owner::CurrentUser,
                 Some(Keyword::CURRENT_ROLE) => Owner::CurrentRole,
                 Some(Keyword::SESSION_USER) => Owner::SessionUser,
@@ -6556,6 +6556,18 @@ impl<'a> Parser<'a> {
             };
 
             AlterTableOperation::OwnerTo { new_owner }
+        } else if dialect_of!(self is ClickHouseDialect|GenericDialect)
+            && self.parse_keyword(Keyword::ATTACH)
+        {
+            AlterTableOperation::AttachPartition {
+                partition: self.parse_part_or_partition()?,
+            }
+        } else if dialect_of!(self is ClickHouseDialect|GenericDialect)
+            && self.parse_keyword(Keyword::DETACH)
+        {
+            AlterTableOperation::DetachPartition {
+                partition: self.parse_part_or_partition()?,
+            }
         } else {
             let options: Vec<SqlOption> =
                 self.parse_options_with_keywords(&[Keyword::SET, Keyword::TBLPROPERTIES])?;
@@ -6573,6 +6585,16 @@ impl<'a> Parser<'a> {
         Ok(operation)
     }
 
+    fn parse_part_or_partition(&mut self) -> Result<Partition, ParserError> {
+        let keyword = self.expect_one_of_keywords(&[Keyword::PART, Keyword::PARTITION])?;
+        match keyword {
+            Keyword::PART => Ok(Partition::Part(self.parse_expr()?)),
+            Keyword::PARTITION => Ok(Partition::Expr(self.parse_expr()?)),
+            // unreachable because expect_one_of_keywords used above
+            _ => unreachable!(),
+        }
+    }
+
     pub fn parse_alter(&mut self) -> Result<Statement, ParserError> {
         let object_type = self.expect_one_of_keywords(&[
             Keyword::VIEW,

tests/sqlparser_clickhouse.rs

@@ -222,6 +222,71 @@ fn parse_create_table() {
     );
 }
 
+#[test]
+fn parse_alter_table_attach_and_detach_partition() {
+    for operation in &["ATTACH", "DETACH"] {
+        match clickhouse_and_generic()
+            .verified_stmt(format!("ALTER TABLE t0 {operation} PARTITION part").as_str())
+        {
+            Statement::AlterTable {
+                name, operations, ..
+            } => {
+                pretty_assertions::assert_eq!("t0", name.to_string());
+                pretty_assertions::assert_eq!(
+                    operations[0],
+                    if operation == &"ATTACH" {
+                        AlterTableOperation::AttachPartition {
+                            partition: Partition::Expr(Identifier(Ident::new("part")))
+                        }
+                    } else {
+                        AlterTableOperation::DetachPartition {
+                            partition: Partition::Expr(Identifier(Ident::new("part")))
+                        }
+                    }
+                );
+            }
+            _ => unreachable!(),
+        }
+
+        match clickhouse_and_generic()
+            .verified_stmt(format!("ALTER TABLE t1 {operation} PART part").as_str())
+        {
+            Statement::AlterTable {
+                name, operations, ..
+            } => {
+                pretty_assertions::assert_eq!("t1", name.to_string());
+                pretty_assertions::assert_eq!(
+                    operations[0],
+                    if operation == &"ATTACH" {
+                        AlterTableOperation::AttachPartition {
+                            partition: Partition::Part(Identifier(Ident::new("part")))
+                        }
+                    } else {
+                        AlterTableOperation::DetachPartition {
+                            partition: Partition::Part(Identifier(Ident::new("part")))
+                        }
+                    }
+                );
+            }
+            _ => unreachable!(),
+        }
+
+        // negative cases
+        assert_eq!(
+            clickhouse_and_generic()
+                .parse_sql_statements(format!("ALTER TABLE t0 {operation} PARTITION").as_str())
+                .unwrap_err(),
+            ParserError("Expected: an expression:, found: EOF".to_string())
+        );
+        assert_eq!(
+            clickhouse_and_generic()
+                .parse_sql_statements(format!("ALTER TABLE t0 {operation} PART").as_str())
+                .unwrap_err(),
+            ParserError("Expected: an expression:, found: EOF".to_string())
+        );
+    }
+}
+
 #[test]
 fn parse_optimize_table() {
     clickhouse_and_generic().verified_stmt("OPTIMIZE TABLE t0");