fix: warn for OFFSET without ORDER BY

added warning for offset without order

5 files changed, 20 insertions, 1 deletions

diff --git a/ydb/library/yql/core/issue/protos/issue_id.proto b/ydb/library/yql/core/issue/protos/issue_id.proto
index f866325f0f4..67a7c6b0b19 100644
--- a/ydb/library/yql/core/issue/protos/issue_id.proto
+++ b/ydb/library/yql/core/issue/protos/issue_id.proto
@@ -138,6 +138,7 @@ message TIssuesIds {
         YQL_UNUSED_HINT = 4534;
         YQL_DEPRECATED_POSITIONAL_SCHEMA = 4535;
         YQL_DUPLICATE_DECLARE = 4536;
+        YQL_OFFSET_WITHOUT_SORT = 4537;
 
 // yql parser errors
         YQL_NOT_ALLOWED_IN_DISCOVERY = 4600;
diff --git a/ydb/library/yql/core/issue/yql_issue.txt b/ydb/library/yql/core/issue/yql_issue.txt
index bde10483c60..2dd72cb447e 100644
--- a/ydb/library/yql/core/issue/yql_issue.txt
+++ b/ydb/library/yql/core/issue/yql_issue.txt
@@ -623,4 +623,8 @@ ids {
 ids {
   code: YT_FOLDER_INPUT_IS_NOT_A_FOLDER
   severity: S_ERROR
+}
+ids {
+  code: YQL_OFFSET_WITHOUT_SORT
+  severity: S_WARNING
 }
\ No newline at end of file
diff --git a/ydb/library/yql/sql/v1/node.cpp b/ydb/library/yql/sql/v1/node.cpp
index d69193ec018..bb5e410e777 100644
--- a/ydb/library/yql/sql/v1/node.cpp
+++ b/ydb/library/yql/sql/v1/node.cpp
@@ -293,6 +293,10 @@ const TString* INode::ModuleName() const {
     return nullptr;
 }
 
+bool INode::HasSkip() const {
+    return false;
+}
+
 void INode::VisitTree(const TVisitFunc& func) const {
     TVisitNodeSet visited;
     VisitTree(func, visited);
diff --git a/ydb/library/yql/sql/v1/node.h b/ydb/library/yql/sql/v1/node.h
index 84be0f9be12..633143aa34c 100644
--- a/ydb/library/yql/sql/v1/node.h
+++ b/ydb/library/yql/sql/v1/node.h
@@ -169,6 +169,7 @@ namespace NSQLTranslationV1 {
         virtual bool IsSelect() const;
         virtual const TString* FuncName() const;
         virtual const TString* ModuleName() const;
+        virtual bool HasSkip() const;
 
         using TVisitFunc = std::function<bool (const INode&)>;
         using TVisitNodeSet = std::unordered_set<const INode*>;
diff --git a/ydb/library/yql/sql/v1/select.cpp b/ydb/library/yql/sql/v1/select.cpp
index f1de60ba734..e2dd68db4ee 100644
--- a/ydb/library/yql/sql/v1/select.cpp
+++ b/ydb/library/yql/sql/v1/select.cpp
@@ -2697,7 +2697,7 @@ TSourcePtr BuildOverWindowSource(TPosition pos, const TString& windowName, ISour
 class TSkipTakeNode final: public TAstListNode {
 public:
     TSkipTakeNode(TPosition pos, const TNodePtr& skip, const TNodePtr& take)
-        : TAstListNode(pos)
+        : TAstListNode(pos), IsSkipProvided_(!!skip)
     {
         TNodePtr select(AstNode("select"));
         if (skip) {
@@ -2710,6 +2710,12 @@ public:
     TPtr DoClone() const final {
         return {};
     }
+
+    bool HasSkip() const {
+        return IsSkipProvided_;
+    }
+private:
+    const bool IsSkipProvided_;
 };
 
 TNodePtr BuildSkipTake(TPosition pos, const TNodePtr& skip, const TNodePtr& take) {
@@ -2743,6 +2749,9 @@ public:
             if (!SkipTake->Init(ctx, FakeSource.Get())) {
                 return false;
             }
+            if (SkipTake->HasSkip() && EOrderKind::Sort != Source->GetOrderKind()) {
+                ctx.Warning(Source->GetPos(), TIssuesIds::YQL_OFFSET_WITHOUT_SORT) << "LIMIT with OFFSET without ORDER BY may provide different results from run to run";
+            }
         }
 
         return true;