Add SHOW CREATE QUOTA statement parsing

Add ShowCreateQuotaQuery AST node to properly handle SHOW CREATE QUOTA
statements. The EXPLAIN output format is "SHOW CREATE QUOTA query" to
match ClickHouse's expected output.

Author: claude

ast/ast.go

@@ -629,6 +629,16 @@ func (s *ShowPrivilegesQuery) Pos() token.Position { return s.Position }
 func (s *ShowPrivilegesQuery) End() token.Position { return s.Position }
 func (s *ShowPrivilegesQuery) statementNode()      {}
 
+// ShowCreateQuotaQuery represents a SHOW CREATE QUOTA statement.
+type ShowCreateQuotaQuery struct {
+	Position token.Position `json:"-"`
+	Name     string         `json:"name,omitempty"`
+}
+
+func (s *ShowCreateQuotaQuery) Pos() token.Position { return s.Position }
+func (s *ShowCreateQuotaQuery) End() token.Position { return s.Position }
+func (s *ShowCreateQuotaQuery) statementNode()      {}
+
 // -----------------------------------------------------------------------------
 // Expressions
 

internal/explain/explain.go

@@ -117,6 +117,8 @@ func Node(sb *strings.Builder, node interface{}, depth int) {
 		explainShowQuery(sb, n, indent)
 	case *ast.ShowPrivilegesQuery:
 		fmt.Fprintf(sb, "%sShowPrivilegesQuery\n", indent)
+	case *ast.ShowCreateQuotaQuery:
+		fmt.Fprintf(sb, "%sSHOW CREATE QUOTA query\n", indent)
 	case *ast.UseQuery:
 		explainUseQuery(sb, n, indent)
 	case *ast.DescribeQuery:

parser/parser.go

@@ -2642,16 +2642,20 @@ func (p *Parser) parseShow() ast.Statement {
 		if p.currentIs(token.DATABASE) {
 			show.ShowType = ast.ShowCreateDB
 			p.nextToken()
+		} else if p.currentIs(token.IDENT) && strings.ToUpper(p.current.Value) == "QUOTA" {
+			// SHOW CREATE QUOTA <name>
+			p.nextToken()
+			name := ""
+			if p.currentIs(token.IDENT) || p.current.Token.IsKeyword() {
+				name = p.current.Value
+				p.nextToken()
+			}
+			return &ast.ShowCreateQuotaQuery{Position: pos, Name: name}
 		} else {
 			show.ShowType = ast.ShowCreate
-			// Handle SHOW CREATE TABLE, SHOW CREATE QUOTA, etc.
+			// Handle SHOW CREATE TABLE, etc.
 			if p.currentIs(token.TABLE) {
 				p.nextToken()
-			} else if p.currentIs(token.DEFAULT) || (p.currentIs(token.IDENT) && strings.ToUpper(p.current.Value) == "QUOTA") {
-				// SHOW CREATE QUOTA default - skip QUOTA keyword
-				if p.currentIs(token.IDENT) && strings.ToUpper(p.current.Value) == "QUOTA" {
-					p.nextToken()
-				}
 			}
 		}
 	case token.SETTINGS:

parser/testdata/01033_quota_dcl/metadata.json

@@ -1 +1 @@
-{"todo": true}
+{}