YQL-17269: Support UNION/INTERSECT/EXCEPT combinations

Introduce `UNION` and `INTERSECT/EXCEPT` grammar rules
for precedence. Rewrote `Build` procedure into `BuildStmt`,
`BuildUnion`, `BuildIntersection`. Added tests, modify format.

It took a lot of time trying to adapt the existing `Build` procedure.
The I noticed that the logic for `union` and `intersection` is
different, since `union` groups arguments into bundles, but
`intersection` is a strictly binary operation.
commit_hash:70008ae3c2603364b6dfbeeb189fdc7f5237433d

1 files changed, 29 insertions, 2 deletions

diff --git a/yql/essentials/sql/v1/sql_select.h b/yql/essentials/sql/v1/sql_select.h
index fd6f0bece52..3224a3ca3b3 100644
--- a/yql/essentials/sql/v1/sql_select.h
+++ b/yql/essentials/sql/v1/sql_select.h
@@ -62,9 +62,36 @@ private:
     bool ValidateLimitOrderByWithSelectOp(TMaybe<TSelectKindPlacement> placement, TStringBuf what);
     bool NeedPassLimitOrderByToUnderlyingSelect(TMaybe<TSelectKindPlacement> placement);
 
-    template<typename TRule>
-    TSourcePtr Build(const TRule& node, TPosition pos, TSelectKindResult&& first);
+    struct TBuildExtra {
+        TSelectKindResult First;
+        TPosition FirstPos;
+        TSelectKindResult Last;
+    };
 
+    template <typename TRule>
+        requires std::same_as<TRule, TRule_union_op> ||
+                 std::same_as<TRule, TRule_intersect_op>
+    bool IsAllQualifiedOp(const TRule& node);
+
+    template <typename TRule>
+        requires std::same_as<TRule, TRule_select_stmt> ||
+                 std::same_as<TRule, TRule_select_unparenthesized_stmt>
+    TSourcePtr BuildStmt(const TRule& node, TPosition& pos);
+
+    template <typename TRule>
+        requires std::same_as<TRule, TRule_select_stmt> ||
+                 std::same_as<TRule, TRule_select_unparenthesized_stmt>
+    TSourcePtr BuildUnion(const TRule& node, TPosition& pos, TBuildExtra& extra);
+
+    template <typename TRule>
+        requires std::same_as<TRule, TRule_select_stmt_intersect> ||
+                 std::same_as<TRule, TRule_select_unparenthesized_stmt_intersect>
+    TSourcePtr BuildExceptionIntersection(const TRule& node, TPosition& pos, TSelectKindPlacement placement, TBuildExtra& extra);
+
+    template <typename TRule>
+        requires std::same_as<TRule, TRule_select_kind_parenthesis> ||
+                 std::same_as<TRule, TRule_select_kind_partial>
+    TSelectKindResult BuildAtom(const TRule& node, TPosition& pos, TSelectKindPlacement placement, TBuildExtra& extra);
 
     TSelectKindResult SelectKind(const TRule_select_kind& node, TPosition& selectPos, TMaybe<TSelectKindPlacement> placement);
     TSelectKindResult SelectKind(const TRule_select_kind_partial& node, TPosition& selectPos, TMaybe<TSelectKindPlacement> placement);