Fix EXPLAIN type handling in viewExplain for subqueries

- Only show explicit EXPLAIN type when it's not AST or PLAN (default)
- EXPLAIN SYNTAX correctly outputs 'EXPLAIN SYNTAX'
- EXPLAIN or EXPLAIN PLAN outputs just 'EXPLAIN'

Fixes many tests with EXPLAIN subqueries (comma_join, window functions, etc.)

Author: claude

internal/explain/tables.go

@@ -149,8 +149,13 @@ func explainViewExplain(sb *strings.Builder, n *ast.ExplainQuery, alias string,
 	// Now output the viewExplain function
 	fmt.Fprintf(sb, "%s       Function viewExplain (children %d)\n", indent, 1)
 	fmt.Fprintf(sb, "%s        ExpressionList (children %d)\n", indent, 3)
-	// First argument: 'EXPLAIN' literal
-	fmt.Fprintf(sb, "%s         Literal \\'EXPLAIN\\'\n", indent)
+	// First argument: 'EXPLAIN' or 'EXPLAIN SYNTAX' etc.
+	// PLAN is the default and never shown; only show non-default types like SYNTAX
+	explainTypeStr := "EXPLAIN"
+	if n.ExplicitType && n.ExplainType != "" && n.ExplainType != ast.ExplainAST && n.ExplainType != ast.ExplainPlan {
+		explainTypeStr = "EXPLAIN " + string(n.ExplainType)
+	}
+	fmt.Fprintf(sb, "%s         Literal \\'%s\\'\n", indent, explainTypeStr)
 	// Second argument: options string (e.g., "actions = 1")
 	options := n.OptionsString
 	fmt.Fprintf(sb, "%s         Literal \\'%s\\'\n", indent, options)

parser/testdata/00849_multiple_comma_join_2/metadata.json

@@ -1,34 +1 @@
-{
-  "explain_todo": {
-    "stmt13": true,
-    "stmt14": true,
-    "stmt15": true,
-    "stmt16": true,
-    "stmt17": true,
-    "stmt18": true,
-    "stmt19": true,
-    "stmt20": true,
-    "stmt21": true,
-    "stmt22": true,
-    "stmt23": true,
-    "stmt24": true,
-    "stmt25": true,
-    "stmt26": true,
-    "stmt27": true,
-    "stmt28": true,
-    "stmt29": true,
-    "stmt30": true,
-    "stmt31": true,
-    "stmt32": true,
-    "stmt33": true,
-    "stmt34": true,
-    "stmt35": true,
-    "stmt36": true,
-    "stmt37": true,
-    "stmt38": true,
-    "stmt39": true,
-    "stmt40": true,
-    "stmt41": true,
-    "stmt42": true
-  }
-}
+{}

parser/testdata/02382_join_and_filtering_set/metadata.json

@@ -1,6 +1 @@
-{
-  "explain_todo": {
-    "stmt16": true,
-    "stmt17": true
-  }
-}
+{}

parser/testdata/02493_max_streams_for_merge_tree_reading/metadata.json

@@ -1 +1 @@
-{"explain_todo":{"stmt10":true,"stmt12":true,"stmt14":true,"stmt17":true,"stmt19":true,"stmt8":true}}
+{}

parser/testdata/02676_distinct_reading_in_order_analyzer/metadata.json

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

parser/testdata/02723_parallelize_output_setting/metadata.json

@@ -1 +1 @@
-{"explain_todo":{"stmt4":true,"stmt6":true,"stmt8":true}}
+{}

parser/testdata/02862_sorted_distinct_sparse_fix/metadata.json

@@ -1,6 +1,5 @@
 {
   "explain_todo": {
-    "stmt10": true,
     "stmt4": true
   }
 }

parser/testdata/02863_delayed_source_with_totals_and_extremes/metadata.json

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

parser/testdata/02884_parallel_window_functions/metadata.json

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

parser/testdata/02911_join_on_nullsafe_optimization/metadata.json

@@ -6,10 +6,7 @@
     "stmt18": true,
     "stmt19": true,
     "stmt20": true,
-    "stmt30": true,
-    "stmt31": true,
     "stmt32": true,
-    "stmt33": true,
-    "stmt34": true
+    "stmt33": true
   }
 }