Add CREATE INDEX TYPE/GRANULARITY and DROP INDEX support

1. CREATE INDEX: Added parsing for TYPE and GRANULARITY clauses.
   Updated explain output to include Function node for the index type.
   Fixed IF NOT EXISTS ordering (comes before index name).

2. DROP INDEX: Added Index field to DropQuery, parsing for
   "DROP INDEX name ON table", and DropIndexQuery explain output.

This fixes all 10 statements in 02319_sql_standard_create_drop_index.

Author: claude

ast/ast.go

@@ -503,6 +503,7 @@ type DropQuery struct {
 	Policy          string             `json:"policy,omitempty"`   // For DROP POLICY
 	RowPolicy       string             `json:"row_policy,omitempty"` // For DROP ROW POLICY
 	SettingsProfile string             `json:"settings_profile,omitempty"` // For DROP SETTINGS PROFILE
+	Index           string             `json:"index,omitempty"`            // For DROP INDEX
 	Temporary       bool               `json:"temporary,omitempty"`
 	OnCluster       string             `json:"on_cluster,omitempty"`
 	DropDatabase    bool               `json:"drop_database,omitempty"`
@@ -1107,10 +1108,12 @@ func (d *DropWorkloadQuery) statementNode()      {}
 
 // CreateIndexQuery represents a CREATE INDEX statement.
 type CreateIndexQuery struct {
-	Position  token.Position `json:"-"`
-	IndexName string         `json:"index_name"`
-	Table     string         `json:"table"`
-	Columns   []Expression   `json:"columns,omitempty"`
+	Position    token.Position `json:"-"`
+	IndexName   string         `json:"index_name"`
+	Table       string         `json:"table"`
+	Columns     []Expression   `json:"columns,omitempty"`
+	Type        string         `json:"type,omitempty"`        // Index type (minmax, bloom_filter, etc.)
+	Granularity int            `json:"granularity,omitempty"` // GRANULARITY value
 }
 
 func (c *CreateIndexQuery) Pos() token.Position { return c.Position }

internal/explain/statements.go

@@ -473,6 +473,14 @@ func explainDropQuery(sb *strings.Builder, n *ast.DropQuery, indent string, dept
 		return
 	}
 
+	// DROP INDEX - outputs as DropIndexQuery with two spaces before table name
+	if n.Index != "" {
+		fmt.Fprintf(sb, "%sDropIndexQuery  %s (children %d)\n", indent, n.Table, 2)
+		fmt.Fprintf(sb, "%s Identifier %s\n", indent, n.Index)
+		fmt.Fprintf(sb, "%s Identifier %s\n", indent, n.Table)
+		return
+	}
+
 	// Handle multiple tables: DROP TABLE t1, t2, t3
 	if len(n.Tables) > 1 {
 		fmt.Fprintf(sb, "%sDropQuery   (children %d)\n", indent, 1)
@@ -1564,8 +1572,13 @@ func explainCreateIndexQuery(sb *strings.Builder, n *ast.CreateIndexQuery, inden
 	// Child 1: Index name
 	fmt.Fprintf(sb, "%s Identifier %s\n", indent, n.IndexName)
 
-	// Child 2: Index wrapper with columns
-	fmt.Fprintf(sb, "%s Index (children 1)\n", indent)
+	// Child 2: Index wrapper with columns and type
+	// Index has 1 child for columns-only, 2 children if TYPE is specified
+	indexChildren := 1
+	if n.Type != "" {
+		indexChildren = 2
+	}
+	fmt.Fprintf(sb, "%s Index (children %d)\n", indent, indexChildren)
 
 	// For single column, output as Identifier
 	// For multiple columns or if there are any special cases, output as Function tuple
@@ -1583,6 +1596,12 @@ func explainCreateIndexQuery(sb *strings.Builder, n *ast.CreateIndexQuery, inden
 		fmt.Fprintf(sb, "%s   ExpressionList\n", indent)
 	}
 
+	// Output TYPE as Function with empty ExpressionList
+	if n.Type != "" {
+		fmt.Fprintf(sb, "%s  Function %s (children 1)\n", indent, n.Type)
+		fmt.Fprintf(sb, "%s   ExpressionList\n", indent)
+	}
+
 	// Child 3: Table name
 	fmt.Fprintf(sb, "%s Identifier %s\n", indent, n.Table)
 }

parser/parser.go

@@ -1854,10 +1854,7 @@ func (p *Parser) parseCreateIndex(pos token.Position) *ast.CreateIndexQuery {
 		Position: pos,
 	}
 
-	// Parse index name
-	query.IndexName = p.parseIdentifierName()
-
-	// Skip IF NOT EXISTS if present
+	// Skip IF NOT EXISTS if present (comes before index name)
 	if p.currentIs(token.IF) {
 		p.nextToken() // IF
 		if p.currentIs(token.NOT) {
@@ -1868,6 +1865,9 @@ func (p *Parser) parseCreateIndex(pos token.Position) *ast.CreateIndexQuery {
 		}
 	}
 
+	// Parse index name
+	query.IndexName = p.parseIdentifierName()
+
 	// Expect ON
 	if p.currentIs(token.ON) {
 		p.nextToken()
@@ -1905,6 +1905,22 @@ func (p *Parser) parseCreateIndex(pos token.Position) *ast.CreateIndexQuery {
 		}
 	}
 
+	// Parse TYPE clause
+	if p.currentIs(token.IDENT) && strings.ToUpper(p.current.Value) == "TYPE" {
+		p.nextToken() // skip TYPE
+		query.Type = p.parseIdentifierName()
+	}
+
+	// Parse GRANULARITY clause
+	if p.currentIs(token.IDENT) && strings.ToUpper(p.current.Value) == "GRANULARITY" {
+		p.nextToken() // skip GRANULARITY
+		if p.currentIs(token.NUMBER) {
+			val, _ := strconv.Atoi(p.current.Value)
+			query.Granularity = val
+			p.nextToken()
+		}
+	}
+
 	return query
 }
 
@@ -4021,6 +4037,7 @@ func (p *Parser) parseDrop() *ast.DropQuery {
 		dropFunction = true
 		p.nextToken()
 	case token.INDEX:
+		drop.Index = "_pending_"
 		p.nextToken()
 	case token.SETTINGS:
 		// DROP SETTINGS PROFILE
@@ -4116,6 +4133,20 @@ func (p *Parser) parseDrop() *ast.DropQuery {
 			drop.RowPolicy = tableName
 		} else if drop.SettingsProfile == "_pending_" {
 			drop.SettingsProfile = tableName
+		} else if drop.Index == "_pending_" {
+			drop.Index = tableName
+			// For DROP INDEX, parse ON table_name
+			if p.currentIs(token.ON) {
+				p.nextToken() // skip ON
+				tableNamePart := p.parseIdentifierName()
+				if p.currentIs(token.DOT) {
+					p.nextToken()
+					drop.Database = tableNamePart
+					drop.Table = p.parseIdentifierName()
+				} else {
+					drop.Table = tableNamePart
+				}
+			}
 		} else if dropDictionary {
 			drop.Dictionary = tableName
 			// Also set Table/Tables for backward compatibility with AST JSON

parser/testdata/02319_sql_standard_create_drop_index/metadata.json

@@ -1,14 +1 @@
-{
-  "explain_todo": {
-    "stmt14": true,
-    "stmt15": true,
-    "stmt16": true,
-    "stmt21": true,
-    "stmt22": true,
-    "stmt3": true,
-    "stmt4": true,
-    "stmt5": true,
-    "stmt8": true,
-    "stmt9": true
-  }
-}
+{}