feat(dsql): parse ALTER COLUMN drop forms

Cargo.toml

@@ -17,8 +17,8 @@
 
 [package]
 name = "sqlparser-dsql"
-description = "SQL parser fork with Aurora DSQL extensions (CREATE INDEX ASYNC, ALTER TABLE ASYNC, ALTER COLUMN SET STORAGE, order-independent CREATE SEQUENCE, INCLUDE on table constraints). Based on sqlparser 0.62.0."
-version = "0.62.4"
+description = "SQL parser fork with Aurora DSQL extensions (CREATE INDEX ASYNC, ALTER TABLE ASYNC, ALTER COLUMN DROP IDENTITY/EXPRESSION, ALTER COLUMN SET STORAGE, order-independent CREATE SEQUENCE, INCLUDE on table constraints). Based on sqlparser 0.62.0."
+version = "0.62.5"
 authors = [
     "Apache DataFusion <dev@datafusion.apache.org>",
     "Amazon Web Services",

src/ast/ddl.rs

@@ -1278,6 +1278,16 @@ pub enum AlterColumnOperation {
     },
     /// `DROP DEFAULT`
     DropDefault,
+    /// `DROP IDENTITY [ IF EXISTS ]`
+    DropIdentity {
+        /// Whether `IF EXISTS` was specified.
+        if_exists: bool,
+    },
+    /// `DROP EXPRESSION [ IF EXISTS ]`
+    DropExpression {
+        /// Whether `IF EXISTS` was specified.
+        if_exists: bool,
+    },
     /// `SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN | DEFAULT }`
     SetStorage {
         /// PostgreSQL column storage strategy.
@@ -1315,6 +1325,20 @@ impl fmt::Display for AlterColumnOperation {
             AlterColumnOperation::DropDefault => {
                 write!(f, "DROP DEFAULT")
             }
+            AlterColumnOperation::DropIdentity { if_exists } => {
+                write!(f, "DROP IDENTITY")?;
+                if *if_exists {
+                    write!(f, " IF EXISTS")?;
+                }
+                Ok(())
+            }
+            AlterColumnOperation::DropExpression { if_exists } => {
+                write!(f, "DROP EXPRESSION")?;
+                if *if_exists {
+                    write!(f, " IF EXISTS")?;
+                }
+                Ok(())
+            }
             AlterColumnOperation::SetStorage { storage } => {
                 write!(f, "SET STORAGE {storage}")
             }

src/ast/spans.rs

@@ -893,6 +893,8 @@ impl Spanned for Analyze {
 /// - [AlterColumnOperation::SetNotNull]
 /// - [AlterColumnOperation::DropNotNull]
 /// - [AlterColumnOperation::DropDefault]
+/// - [AlterColumnOperation::DropIdentity]
+/// - [AlterColumnOperation::DropExpression]
 /// - [AlterColumnOperation::SetStorage]
 /// - [AlterColumnOperation::AddGenerated]
 impl Spanned for AlterColumnOperation {
@@ -902,6 +904,8 @@ impl Spanned for AlterColumnOperation {
             AlterColumnOperation::DropNotNull => Span::empty(),
             AlterColumnOperation::SetDefault { value } => value.span(),
             AlterColumnOperation::DropDefault => Span::empty(),
+            AlterColumnOperation::DropIdentity { .. } => Span::empty(),
+            AlterColumnOperation::DropExpression { .. } => Span::empty(),
             AlterColumnOperation::SetStorage { .. } => Span::empty(),
             AlterColumnOperation::SetDataType {
                 data_type: _,

src/keywords.rs

@@ -406,6 +406,7 @@ define_keywords!(
     EXPLAIN,
     EXPLICIT,
     EXPORT,
+    EXPRESSION,
     EXTEND,
     EXTENDED,
     EXTENSION,

src/parser/mod.rs

@@ -10615,6 +10615,14 @@ impl<'a> Parser<'a> {
                 }
             } else if self.parse_keywords(&[Keyword::DROP, Keyword::DEFAULT]) {
                 AlterColumnOperation::DropDefault {}
+            } else if self.parse_keywords(&[Keyword::DROP, Keyword::IDENTITY]) {
+                AlterColumnOperation::DropIdentity {
+                    if_exists: self.parse_keywords(&[Keyword::IF, Keyword::EXISTS]),
+                }
+            } else if self.parse_keywords(&[Keyword::DROP, Keyword::EXPRESSION]) {
+                AlterColumnOperation::DropExpression {
+                    if_exists: self.parse_keywords(&[Keyword::IF, Keyword::EXISTS]),
+                }
             } else if self.parse_keywords(&[Keyword::SET, Keyword::STORAGE]) {
                 let storage = self.parse_column_storage()?;
                 AlterColumnOperation::SetStorage { storage }
@@ -10647,9 +10655,9 @@ impl<'a> Parser<'a> {
                 }
             } else {
                 let message = if is_postgresql {
-                    "SET/DROP NOT NULL, SET DEFAULT, SET STORAGE, SET DATA TYPE, or ADD GENERATED after ALTER COLUMN"
+                    "SET/DROP NOT NULL, SET/DROP DEFAULT, DROP IDENTITY, DROP EXPRESSION, SET STORAGE, SET DATA TYPE, or ADD GENERATED after ALTER COLUMN"
                 } else {
-                    "SET/DROP NOT NULL, SET DEFAULT, SET STORAGE, or SET DATA TYPE after ALTER COLUMN"
+                    "SET/DROP NOT NULL, SET/DROP DEFAULT, DROP IDENTITY, DROP EXPRESSION, SET STORAGE, or SET DATA TYPE after ALTER COLUMN"
                 };
 
                 return self.expected_ref(message, self.peek_token_ref());

tests/sqlparser_postgres.rs

@@ -1110,6 +1110,24 @@ fn parse_alter_table_alter_column_set_storage() {
     }
 }
 
+#[test]
+fn parse_alter_table_alter_column_drop_identity() {
+    for suffix in ["", " IF EXISTS"] {
+        pg_and_generic().verified_stmt(&format!(
+            "ALTER TABLE tab ALTER COLUMN id DROP IDENTITY{suffix}"
+        ));
+    }
+}
+
+#[test]
+fn parse_alter_table_alter_column_drop_expression() {
+    for suffix in ["", " IF EXISTS"] {
+        pg_and_generic().verified_stmt(&format!(
+            "ALTER TABLE tab ALTER COLUMN generated_value DROP EXPRESSION{suffix}"
+        ));
+    }
+}
+
 #[test]
 fn parse_create_table_column_storage() {
     for (storage, expected) in [