Fix 13 parser tests with various EXPLAIN AST improvements

internal/explain/expressions.go

@@ -348,6 +348,10 @@ func explainAliasedExpr(sb *strings.Builder, n *ast.AliasedExpr, depth int) {
 		if e.Type == ast.LiteralArray {
 			if exprs, ok := e.Value.([]ast.Expression); ok {
 				needsFunctionFormat := false
+				// Empty arrays always use Function array format
+				if len(exprs) == 0 {
+					needsFunctionFormat = true
+				}
 				for _, expr := range exprs {
 					// Check for tuples - use Function array
 					if lit, ok := expr.(*ast.Literal); ok && lit.Type == ast.LiteralTuple {
@@ -363,7 +367,11 @@ func explainAliasedExpr(sb *strings.Builder, n *ast.AliasedExpr, depth int) {
 				if needsFunctionFormat {
 					// Render as Function array with alias
 					fmt.Fprintf(sb, "%sFunction array (alias %s) (children %d)\n", indent, n.Alias, 1)
-					fmt.Fprintf(sb, "%s ExpressionList (children %d)\n", indent, len(exprs))
+					if len(exprs) > 0 {
+						fmt.Fprintf(sb, "%s ExpressionList (children %d)\n", indent, len(exprs))
+					} else {
+						fmt.Fprintf(sb, "%s ExpressionList\n", indent)
+					}
 					for _, expr := range exprs {
 						Node(sb, expr, depth+2)
 					}
@@ -427,6 +435,9 @@ func explainAliasedExpr(sb *strings.Builder, n *ast.AliasedExpr, depth int) {
 	case *ast.InExpr:
 		// IN expressions with alias
 		explainInExprWithAlias(sb, e, n.Alias, indent, depth)
+	case *ast.CaseExpr:
+		// CASE expressions with alias
+		explainCaseExprWithAlias(sb, e, n.Alias, indent, depth)
 	default:
 		// For other types, recursively explain and add alias info
 		Node(sb, n.Expr, depth)

internal/explain/functions.go

@@ -707,14 +707,22 @@ func explainIsNullExpr(sb *strings.Builder, n *ast.IsNullExpr, indent string, de
 }
 
 func explainCaseExpr(sb *strings.Builder, n *ast.CaseExpr, indent string, depth int) {
+	explainCaseExprWithAlias(sb, n, "", indent, depth)
+}
+
+func explainCaseExprWithAlias(sb *strings.Builder, n *ast.CaseExpr, alias string, indent string, depth int) {
 	// CASE is represented as Function multiIf or caseWithExpression
 	if n.Operand != nil {
 		// CASE x WHEN ... form
 		argCount := 1 + len(n.Whens)*2 // operand + (condition, result) pairs
 		if n.Else != nil {
 			argCount++
 		}
-		fmt.Fprintf(sb, "%sFunction caseWithExpression (children %d)\n", indent, 1)
+		if alias != "" {
+			fmt.Fprintf(sb, "%sFunction caseWithExpression (alias %s) (children %d)\n", indent, alias, 1)
+		} else {
+			fmt.Fprintf(sb, "%sFunction caseWithExpression (children %d)\n", indent, 1)
+		}
 		fmt.Fprintf(sb, "%s ExpressionList (children %d)\n", indent, argCount)
 		Node(sb, n.Operand, depth+2)
 		for _, w := range n.Whens {
@@ -730,7 +738,11 @@ func explainCaseExpr(sb *strings.Builder, n *ast.CaseExpr, indent string, depth
 		if n.Else != nil {
 			argCount++
 		}
-		fmt.Fprintf(sb, "%sFunction multiIf (children %d)\n", indent, 1)
+		if alias != "" {
+			fmt.Fprintf(sb, "%sFunction multiIf (alias %s) (children %d)\n", indent, alias, 1)
+		} else {
+			fmt.Fprintf(sb, "%sFunction multiIf (children %d)\n", indent, 1)
+		}
 		fmt.Fprintf(sb, "%s ExpressionList (children %d)\n", indent, argCount)
 		for _, w := range n.Whens {
 			Node(sb, w.Condition, depth+2)

internal/explain/statements.go

@@ -70,7 +70,7 @@ func explainCreateQuery(sb *strings.Builder, n *ast.CreateQuery, indent string,
 		return
 	}
 	if n.CreateUser {
-		fmt.Fprintf(sb, "%sCreateUserQuery %s\n", indent, n.UserName)
+		fmt.Fprintf(sb, "%sCreateUserQuery\n", indent)
 		return
 	}
 	if n.CreateDictionary {
@@ -358,11 +358,21 @@ func explainDescribeQuery(sb *strings.Builder, n *ast.DescribeQuery, indent stri
 			fmt.Fprintf(sb, "%s Set\n", indent)
 		}
 	} else {
+		// Regular table describe
 		name := n.Table
 		if n.Database != "" {
 			name = n.Database + "." + n.Table
 		}
-		fmt.Fprintf(sb, "%sDescribe %s\n", indent, name)
+		children := 1
+		if len(n.Settings) > 0 {
+			children++
+		}
+		fmt.Fprintf(sb, "%sDescribeQuery (children %d)\n", indent, children)
+		fmt.Fprintf(sb, "%s TableExpression (children 1)\n", indent)
+		fmt.Fprintf(sb, "%s  TableIdentifier %s\n", indent, name)
+		if len(n.Settings) > 0 {
+			fmt.Fprintf(sb, "%s Set\n", indent)
+		}
 	}
 }
 

internal/explain/tables.go

@@ -30,6 +30,9 @@ func explainTablesInSelectQueryElement(sb *strings.Builder, n *ast.TablesInSelec
 
 func explainTableExpression(sb *strings.Builder, n *ast.TableExpression, indent string, depth int) {
 	children := 1 // table
+	if n.Sample != nil {
+		children++
+	}
 	fmt.Fprintf(sb, "%sTableExpression (children %d)\n", indent, children)
 	// If there's a subquery with an alias, pass the alias to the subquery output
 	if subq, ok := n.Table.(*ast.Subquery); ok {
@@ -51,6 +54,46 @@ func explainTableExpression(sb *strings.Builder, n *ast.TableExpression, indent
 	} else {
 		Node(sb, n.Table, depth+1)
 	}
+	// Output SAMPLE clause if present
+	if n.Sample != nil {
+		explainSampleClause(sb, n.Sample, indent+" ", depth+1)
+	}
+}
+
+func explainSampleClause(sb *strings.Builder, n *ast.SampleClause, indent string, depth int) {
+	// Format the sample ratio as "SampleRatio num / den" or just the expression
+	sb.WriteString(indent)
+	sb.WriteString("SampleRatio ")
+	formatSampleRatio(sb, n.Ratio)
+	sb.WriteString("\n")
+}
+
+func formatSampleRatio(sb *strings.Builder, expr ast.Expression) {
+	// Handle binary expressions like 1 / 2
+	if binExpr, ok := expr.(*ast.BinaryExpr); ok && binExpr.Op == "/" {
+		formatSampleRatioOperand(sb, binExpr.Left)
+		sb.WriteString(" / ")
+		formatSampleRatioOperand(sb, binExpr.Right)
+	} else {
+		formatSampleRatioOperand(sb, expr)
+	}
+}
+
+func formatSampleRatioOperand(sb *strings.Builder, expr ast.Expression) {
+	if lit, ok := expr.(*ast.Literal); ok {
+		switch v := lit.Value.(type) {
+		case int64:
+			fmt.Fprintf(sb, "%d", v)
+		case uint64:
+			fmt.Fprintf(sb, "%d", v)
+		case float64:
+			fmt.Fprintf(sb, "%g", v)
+		default:
+			fmt.Fprintf(sb, "%v", v)
+		}
+	} else {
+		fmt.Fprintf(sb, "%v", expr)
+	}
 }
 
 // explainViewExplain handles EXPLAIN queries used as table sources, converting to viewExplain function

parser/parser.go

@@ -730,6 +730,15 @@ func (p *Parser) parseTableElementWithJoin() *ast.TablesInSelectQueryElement {
 	if p.currentIs(token.COMMA) {
 		p.nextToken()
 		elem.Table = p.parseTableExpression()
+		// ClickHouse adds an empty TableJoin node for comma joins, but only
+		// when the table is NOT a subquery (subqueries don't get TableJoin nodes)
+		if elem.Table != nil {
+			if _, isSubquery := elem.Table.Table.(*ast.Subquery); !isSubquery {
+				elem.Join = &ast.TableJoin{
+					Position: elem.Position,
+				}
+			}
+		}
 		return elem
 	}
 

parser/testdata/01116_cross_count_asterisks/metadata.json

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

parser/testdata/01604_explain_ast_of_nonselect_query/metadata.json

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

parser/testdata/01605_drop_settings_profile_while_assigned/metadata.json

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

parser/testdata/02001_add_default_database_to_system_users/metadata.json

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

parser/testdata/02128_apply_lambda_parsing/metadata.json

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

parser/testdata/02265_cross_join_empty_list/metadata.json

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

parser/testdata/02326_settings_changes_system_table/metadata.json

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

parser/testdata/02467_cross_join_three_table_functions/metadata.json

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

parser/testdata/02469_fix_aliases_parser/metadata.json

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

parser/testdata/02472_segfault_expression_parser/metadata.json

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

parser/testdata/02474_create_user_query_fuzzer_bug/metadata.json

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

parser/testdata/02474_fix_function_parser_bug/metadata.json

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

parser/testdata/02482_if_with_nothing_argument/metadata.json

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

parser/testdata/02896_illegal_sampling/metadata.json

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

parser/testdata/03254_test_alter_user_no_changes/metadata.json

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