Add APPLY column transformer support for asterisk expressions

- Add APPLY token to lexer
- Add Apply field to ast.Asterisk struct
- Add parseAsteriskApply function for parsing APPLY(func) and APPLY func syntax
- Add APPLY to expression precedence for proper infix parsing
- Update explain code to output ColumnsApplyTransformer nodes

This fixes 01470_columns_transformers test and many other tests that use
APPLY column transformers.

Author: claude

ast/ast.go

@@ -1126,6 +1126,7 @@ type Asterisk struct {
 	Table    string          `json:"table,omitempty"`   // for table.*
 	Except   []string        `json:"except,omitempty"`  // for * EXCEPT (col1, col2)
 	Replace  []*ReplaceExpr  `json:"replace,omitempty"` // for * REPLACE (expr AS col)
+	Apply    []string        `json:"apply,omitempty"`   // for * APPLY (func1) APPLY(func2)
 }
 
 func (a *Asterisk) Pos() token.Position { return a.Position }

internal/explain/expressions.go

@@ -529,8 +529,8 @@ func explainAliasedExpr(sb *strings.Builder, n *ast.AliasedExpr, depth int) {
 }
 
 func explainAsterisk(sb *strings.Builder, n *ast.Asterisk, indent string, depth int) {
-	// Check if there are any column transformers (EXCEPT, REPLACE)
-	hasTransformers := len(n.Except) > 0 || len(n.Replace) > 0
+	// Check if there are any column transformers (EXCEPT, REPLACE, APPLY)
+	hasTransformers := len(n.Except) > 0 || len(n.Replace) > 0 || len(n.Apply) > 0
 
 	if n.Table != "" {
 		if hasTransformers {
@@ -559,6 +559,8 @@ func explainColumnsTransformers(sb *strings.Builder, n *ast.Asterisk, indent str
 	if len(n.Replace) > 0 {
 		transformerCount++
 	}
+	// Each APPLY adds one transformer
+	transformerCount += len(n.Apply)
 
 	fmt.Fprintf(sb, "%sColumnsTransformerList (children %d)\n", indent, transformerCount)
 
@@ -583,6 +585,11 @@ func explainColumnsTransformers(sb *strings.Builder, n *ast.Asterisk, indent str
 			}
 		}
 	}
+
+	// Each APPLY function gets its own ColumnsApplyTransformer
+	for range n.Apply {
+		fmt.Fprintf(sb, "%s ColumnsApplyTransformer\n", indent)
+	}
 }
 
 func explainColumnsMatcher(sb *strings.Builder, n *ast.ColumnsMatcher, indent string, depth int) {

parser/expression.go

@@ -49,7 +49,7 @@ func (p *Parser) precedence(tok token.Token) int {
 		return MUL_PREC
 	case token.LPAREN, token.LBRACKET:
 		return CALL
-	case token.EXCEPT, token.REPLACE:
+	case token.EXCEPT, token.REPLACE, token.APPLY:
 		return CALL // For asterisk modifiers
 	case token.COLONCOLON:
 		return CALL // Cast operator
@@ -418,6 +418,12 @@ func (p *Parser) parseInfixExpression(left ast.Expression) ast.Expression {
 			return p.parseAsteriskReplace(asterisk)
 		}
 		return left
+	case token.APPLY:
+		// Handle * APPLY (func) or * APPLY func
+		if asterisk, ok := left.(*ast.Asterisk); ok {
+			return p.parseAsteriskApply(asterisk)
+		}
+		return left
 	case token.NUMBER:
 		// Handle tuple access like t.1 where .1 is lexed as a number
 		if strings.HasPrefix(p.current.Value, ".") {
@@ -2387,3 +2393,25 @@ func (p *Parser) parseAsteriskReplace(asterisk *ast.Asterisk) ast.Expression {
 
 	return asterisk
 }
+
+func (p *Parser) parseAsteriskApply(asterisk *ast.Asterisk) ast.Expression {
+	p.nextToken() // skip APPLY
+
+	// APPLY can have optional parentheses: * APPLY(func) or * APPLY func
+	hasParens := p.currentIs(token.LPAREN)
+	if hasParens {
+		p.nextToken() // skip (
+	}
+
+	// Parse function name (can be IDENT or keyword like sum, avg, etc.)
+	if p.currentIs(token.IDENT) || p.current.Token.IsKeyword() {
+		asterisk.Apply = append(asterisk.Apply, p.current.Value)
+		p.nextToken()
+	}
+
+	if hasParens {
+		p.expect(token.RPAREN)
+	}
+
+	return asterisk
+}

parser/testdata/00157_cache_dictionary/metadata.json

@@ -1,6 +1,5 @@
 {
   "explain_todo": {
-    "stmt2": true,
-    "stmt7": true
+    "stmt2": true
   }
 }

parser/testdata/01018_ddl_dictionaries_create/metadata.json

@@ -1,19 +1,15 @@
 {
   "explain_todo": {
-    "stmt11": true,
     "stmt13": true,
     "stmt17": true,
     "stmt18": true,
     "stmt22": true,
     "stmt23": true,
     "stmt28": true,
-    "stmt35": true,
     "stmt37": true,
     "stmt43": true,
-    "stmt47": true,
     "stmt48": true,
     "stmt51": true,
-    "stmt52": true,
     "stmt53": true
   }
 }

parser/testdata/01018_dictionaries_from_dictionaries/metadata.json

@@ -1,8 +1 @@
-{
-  "explain_todo": {
-    "stmt14": true,
-    "stmt21": true,
-    "stmt6": true,
-    "stmt8": true
-  }
-}
+{}

parser/testdata/01023_materialized_view_query_context/metadata.json

@@ -1,5 +1 @@
-{
-  "explain_todo": {
-    "stmt6": true
-  }
-}
+{}

parser/testdata/01036_no_superfluous_dict_reload_on_create_database_2/metadata.json

@@ -1,6 +1,5 @@
 {
   "explain_todo": {
-    "stmt4": true,
     "stmt9": true
   }
 }

parser/testdata/01048_exists_query/metadata.json

@@ -2,7 +2,6 @@
   "explain_todo": {
     "stmt22": true,
     "stmt23": true,
-    "stmt24": true,
-    "stmt25": true
+    "stmt24": true
   }
 }

parser/testdata/01110_dictionary_layout_without_arguments/metadata.json

@@ -1,6 +1,5 @@
 {
   "explain_todo": {
-    "stmt5": true,
     "stmt7": true,
     "stmt8": true
   }