Fix more parser and explain output issues

- Always expand DataType parameters as children in explain output
- Add HasSettings field to InsertQuery for SETTINGS clause tracking
- Output Set child in InsertQuery explain when settings are present

Test count: 5505 passing (up from 5488)

Author: claude

ast/ast.go

@@ -202,13 +202,14 @@ func (s *SettingExpr) End() token.Position { return s.Position }
 
 // InsertQuery represents an INSERT statement.
 type InsertQuery struct {
-	Position token.Position `json:"-"`
-	Database string         `json:"database,omitempty"`
-	Table    string         `json:"table,omitempty"`
-	Function *FunctionCall  `json:"function,omitempty"` // For INSERT INTO FUNCTION syntax
-	Columns  []*Identifier  `json:"columns,omitempty"`
-	Select   Statement      `json:"select,omitempty"`
-	Format   *Identifier    `json:"format,omitempty"`
+	Position    token.Position `json:"-"`
+	Database    string         `json:"database,omitempty"`
+	Table       string         `json:"table,omitempty"`
+	Function    *FunctionCall  `json:"function,omitempty"` // For INSERT INTO FUNCTION syntax
+	Columns     []*Identifier  `json:"columns,omitempty"`
+	Select      Statement      `json:"select,omitempty"`
+	Format      *Identifier    `json:"format,omitempty"`
+	HasSettings bool           `json:"has_settings,omitempty"` // For SETTINGS clause
 }
 
 func (i *InsertQuery) Pos() token.Position { return i.Position }

internal/explain/statements.go

@@ -18,6 +18,9 @@ func explainInsertQuery(sb *strings.Builder, n *ast.InsertQuery, indent string,
 	if n.Select != nil {
 		children++
 	}
+	if n.HasSettings {
+		children++
+	}
 	// Note: InsertQuery uses 3 spaces after name in ClickHouse explain
 	fmt.Fprintf(sb, "%sInsertQuery   (children %d)\n", indent, children)
 
@@ -34,6 +37,10 @@ func explainInsertQuery(sb *strings.Builder, n *ast.InsertQuery, indent string,
 	if n.Select != nil {
 		Node(sb, n.Select, depth+1)
 	}
+
+	if n.HasSettings {
+		fmt.Fprintf(sb, "%s Set\n", indent)
+	}
 }
 
 func explainCreateQuery(sb *strings.Builder, n *ast.CreateQuery, indent string, depth int) {
@@ -168,37 +175,15 @@ func explainDescribeQuery(sb *strings.Builder, n *ast.DescribeQuery, indent stri
 }
 
 func explainDataType(sb *strings.Builder, n *ast.DataType, indent string, depth int) {
-	// Check if type has nested DataType parameters that should be expanded
-	hasNestedTypes := false
-	for _, p := range n.Parameters {
-		if _, ok := p.(*ast.DataType); ok {
-			hasNestedTypes = true
-			break
-		}
-	}
-
-	// Check if type has complex parameters (expressions, not just literals/types)
-	hasComplexParams := false
-	for _, p := range n.Parameters {
-		if _, ok := p.(*ast.Literal); ok {
-			continue
-		}
-		if _, ok := p.(*ast.DataType); ok {
-			continue
-		}
-		hasComplexParams = true
-		break
-	}
-
-	if (hasNestedTypes || hasComplexParams) && len(n.Parameters) > 0 {
-		// Nested types and complex parameters need to be output as children
+	// If type has parameters, expand them as children
+	if len(n.Parameters) > 0 {
 		fmt.Fprintf(sb, "%sDataType %s (children %d)\n", indent, n.Name, 1)
 		fmt.Fprintf(sb, "%s ExpressionList (children %d)\n", indent, len(n.Parameters))
 		for _, p := range n.Parameters {
 			Node(sb, p, depth+2)
 		}
 	} else {
-		fmt.Fprintf(sb, "%sDataType %s\n", indent, FormatDataType(n))
+		fmt.Fprintf(sb, "%sDataType %s\n", indent, n.Name)
 	}
 }
 

parser/parser.go

@@ -880,8 +880,9 @@ func (p *Parser) parseInsert() *ast.InsertQuery {
 		p.expect(token.RPAREN)
 	}
 
-	// Parse SETTINGS before VALUES (skip for now as it's not in AST)
+	// Parse SETTINGS before VALUES
 	if p.currentIs(token.SETTINGS) {
+		ins.HasSettings = true
 		p.nextToken()
 		// Just parse and skip the settings
 		p.parseSettingsList()