From f3849a3e943e5f0871b89cadbee89051b2fdcaa1 Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Tue, 23 Dec 2025 17:57:30 +0000
Subject: [PATCH] Add SHOW PRIVILEGES statement parsing

Implement parsing for ClickHouse's SHOW PRIVILEGES statement by adding
a new ShowPrivilegesQuery AST type with its own explain output format.
---
 ast/ast.go                                       |  9 +++++++++
 internal/explain/explain.go                      |  2 ++
 parser/parser.go                                 | 16 ++++++++++++----
 .../testdata/01271_show_privileges/metadata.json |  2 +-
 4 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/ast/ast.go b/ast/ast.go
index def0c2215..8fef5608e 100644
--- a/ast/ast.go
+++ b/ast/ast.go
@@ -620,6 +620,15 @@ func (e *ExistsQuery) Pos() token.Position { return e.Position }
 func (e *ExistsQuery) End() token.Position { return e.Position }
 func (e *ExistsQuery) statementNode()      {}
 
+// ShowPrivilegesQuery represents a SHOW PRIVILEGES statement.
+type ShowPrivilegesQuery struct {
+	Position token.Position `json:"-"`
+}
+
+func (s *ShowPrivilegesQuery) Pos() token.Position { return s.Position }
+func (s *ShowPrivilegesQuery) End() token.Position { return s.Position }
+func (s *ShowPrivilegesQuery) statementNode()      {}
+
 // -----------------------------------------------------------------------------
 // Expressions
 
diff --git a/internal/explain/explain.go b/internal/explain/explain.go
index f43fab680..419abd4f0 100644
--- a/internal/explain/explain.go
+++ b/internal/explain/explain.go
@@ -115,6 +115,8 @@ func Node(sb *strings.Builder, node interface{}, depth int) {
 		explainExplainQuery(sb, n, indent, depth)
 	case *ast.ShowQuery:
 		explainShowQuery(sb, n, indent)
+	case *ast.ShowPrivilegesQuery:
+		fmt.Fprintf(sb, "%sShowPrivilegesQuery\n", indent)
 	case *ast.UseQuery:
 		explainUseQuery(sb, n, indent)
 	case *ast.DescribeQuery:
diff --git a/parser/parser.go b/parser/parser.go
index 431897f85..f5657a4f3 100644
--- a/parser/parser.go
+++ b/parser/parser.go
@@ -2612,13 +2612,21 @@ func (p *Parser) parseDescribe() *ast.DescribeQuery {
 	return desc
 }
 
-func (p *Parser) parseShow() *ast.ShowQuery {
-	show := &ast.ShowQuery{
-		Position: p.current.Pos,
-	}
+func (p *Parser) parseShow() ast.Statement {
+	pos := p.current.Pos
 
 	p.nextToken() // skip SHOW
 
+	// Handle SHOW PRIVILEGES first - it has its own statement type
+	if p.currentIs(token.IDENT) && strings.ToUpper(p.current.Value) == "PRIVILEGES" {
+		p.nextToken()
+		return &ast.ShowPrivilegesQuery{Position: pos}
+	}
+
+	show := &ast.ShowQuery{
+		Position: pos,
+	}
+
 	switch p.current.Token {
 	case token.TABLES:
 		show.ShowType = ast.ShowTables
diff --git a/parser/testdata/01271_show_privileges/metadata.json b/parser/testdata/01271_show_privileges/metadata.json
index ef120d978..9e26dfeeb 100644
--- a/parser/testdata/01271_show_privileges/metadata.json
+++ b/parser/testdata/01271_show_privileges/metadata.json
@@ -1 +1 @@
-{"todo": true}
+{}
\ No newline at end of file