From e857a452016d82dfc00398a5483ce9551dff9565 Mon Sep 17 00:00:00 2001
From: Lukasz Stefaniak <lustefaniak@gmail.com>
Date: Mon, 23 Oct 2023 23:55:11 +0200
Subject: [PATCH] Support  `SELECT * EXCEPT/REPLACE` syntax from ClickHouse
 (#1013)

---
 src/ast/query.rs              |  2 ++
 src/parser/mod.rs             | 37 +++++++++++++++++++++++------------
 tests/sqlparser_clickhouse.rs | 18 +++++++++++++++++
 3 files changed, 44 insertions(+), 13 deletions(-)

diff --git a/src/ast/query.rs b/src/ast/query.rs
index 824fab1b..4289b0bd 100644
--- a/src/ast/query.rs
+++ b/src/ast/query.rs
@@ -434,11 +434,13 @@ pub struct WildcardAdditionalOptions {
     /// `[EXCLUDE...]`.
     pub opt_exclude: Option<ExcludeSelectItem>,
     /// `[EXCEPT...]`.
+    ///  Clickhouse syntax: <https://clickhouse.com/docs/en/sql-reference/statements/select#except>
     pub opt_except: Option<ExceptSelectItem>,
     /// `[RENAME ...]`.
     pub opt_rename: Option<RenameSelectItem>,
     /// `[REPLACE]`
     ///  BigQuery syntax: <https://cloud.google.com/bigquery/docs/reference/standard-sql/query-syntax#select_replace>
+    ///  Clickhouse syntax: <https://clickhouse.com/docs/en/sql-reference/statements/select#replace>
     pub opt_replace: Option<ReplaceSelectItem>,
 }
 
diff --git a/src/parser/mod.rs b/src/parser/mod.rs
index 1c1d8b23..9e0d595c 100644
--- a/src/parser/mod.rs
+++ b/src/parser/mod.rs
@@ -6993,7 +6993,8 @@ impl<'a> Parser<'a> {
         } else {
             None
         };
-        let opt_except = if dialect_of!(self is GenericDialect | BigQueryDialect) {
+        let opt_except = if dialect_of!(self is GenericDialect | BigQueryDialect | ClickHouseDialect)
+        {
             self.parse_optional_select_item_except()?
         } else {
             None
@@ -7004,7 +7005,8 @@ impl<'a> Parser<'a> {
             None
         };
 
-        let opt_replace = if dialect_of!(self is GenericDialect | BigQueryDialect) {
+        let opt_replace = if dialect_of!(self is GenericDialect | BigQueryDialect | ClickHouseDialect)
+        {
             self.parse_optional_select_item_replace()?
         } else {
             None
@@ -7047,18 +7049,27 @@ impl<'a> Parser<'a> {
         &mut self,
     ) -> Result<Option<ExceptSelectItem>, ParserError> {
         let opt_except = if self.parse_keyword(Keyword::EXCEPT) {
-            let idents = self.parse_parenthesized_column_list(Mandatory, false)?;
-            match &idents[..] {
-                [] => {
-                    return self.expected(
-                        "at least one column should be parsed by the expect clause",
-                        self.peek_token(),
-                    )?;
+            if self.peek_token().token == Token::LParen {
+                let idents = self.parse_parenthesized_column_list(Mandatory, false)?;
+                match &idents[..] {
+                    [] => {
+                        return self.expected(
+                            "at least one column should be parsed by the expect clause",
+                            self.peek_token(),
+                        )?;
+                    }
+                    [first, idents @ ..] => Some(ExceptSelectItem {
+                        first_element: first.clone(),
+                        additional_elements: idents.to_vec(),
+                    }),
                 }
-                [first, idents @ ..] => Some(ExceptSelectItem {
-                    first_element: first.clone(),
-                    additional_elements: idents.to_vec(),
-                }),
+            } else {
+                // Clickhouse allows EXCEPT column_name
+                let ident = self.parse_identifier()?;
+                Some(ExceptSelectItem {
+                    first_element: ident,
+                    additional_elements: vec![],
+                })
             }
         } else {
             None
diff --git a/tests/sqlparser_clickhouse.rs b/tests/sqlparser_clickhouse.rs
index 9efe4a36..8cca0da0 100644
--- a/tests/sqlparser_clickhouse.rs
+++ b/tests/sqlparser_clickhouse.rs
@@ -355,6 +355,24 @@ fn parse_limit_by() {
     );
 }
 
+#[test]
+fn parse_select_star_except() {
+    clickhouse().verified_stmt("SELECT * EXCEPT (prev_status) FROM anomalies");
+}
+
+#[test]
+fn parse_select_star_except_no_parens() {
+    clickhouse().one_statement_parses_to(
+        "SELECT * EXCEPT prev_status FROM anomalies",
+        "SELECT * EXCEPT (prev_status) FROM anomalies",
+    );
+}
+
+#[test]
+fn parse_select_star_replace() {
+    clickhouse().verified_stmt("SELECT * REPLACE (i + 1 AS i) FROM columns_transformers");
+}
+
 fn clickhouse() -> TestedDialects {
     TestedDialects {
         dialects: vec![Box::new(ClickHouseDialect {})],