EXISTS with tables YQL-19496

commit_hash:76639a66853d8a9d514e4b11f47e14e2d26e26c4

2 files changed, 20 insertions, 2 deletions

diff --git a/yql/essentials/sql/v1/select.cpp b/yql/essentials/sql/v1/select.cpp
index bf8287e89a3..a916517d885 100644
--- a/yql/essentials/sql/v1/select.cpp
+++ b/yql/essentials/sql/v1/select.cpp
@@ -338,7 +338,10 @@ protected:
     }
 
     void GetInputTables(TTableList& tableList) const override {
-        Source->GetInputTables(tableList);
+        if (Source) {
+            Source->GetInputTables(tableList);
+        }
+
         ISource::GetInputTables(tableList);
     }
 
diff --git a/yql/essentials/sql/v1/sql_expression.cpp b/yql/essentials/sql/v1/sql_expression.cpp
index 199f15f2939..c2074cb50d9 100644
--- a/yql/essentials/sql/v1/sql_expression.cpp
+++ b/yql/essentials/sql/v1/sql_expression.cpp
@@ -1308,7 +1308,22 @@ TNodePtr TSqlExpression::ExistsRule(const TRule_exists_expr& rule) {
         return nullptr;
     }
     const bool checkExist = true;
-    return BuildBuiltinFunc(Ctx, Ctx.Pos(), "ListHasItems", {BuildSourceNode(pos, std::move(source), checkExist)});
+    auto select = BuildSourceNode(Ctx.Pos(), source, checkExist);
+    if (Ctx.Settings.EmitReadsForExists) {
+        TTableList tableList;
+        source->GetInputTables(tableList);
+
+        TNodePtr inputTables(BuildInputTables(Ctx.Pos(), tableList, false, Ctx.Scoped));
+        if (!inputTables->Init(Ctx, source.Get())) {
+            return nullptr;
+        }
+
+        auto node = inputTables;
+        node = node->L(node, node->Y("return", select));
+        select = node->Y("block", node->Q(node));
+    }
+
+    return BuildBuiltinFunc(Ctx, Ctx.Pos(), "ListHasItems", {select});
 }
 
 TNodePtr TSqlExpression::CaseRule(const TRule_case_expr& rule) {