Add global counter to subqueries

dbms/src/Interpreters/QueryAliasesVisitor.cpp

@@ -67,18 +67,18 @@ void QueryAliasesVisitor::getNodeAlias(const ASTPtr & ast, Aliases & aliases, co
     }
     else if (auto subquery = typeid_cast<ASTSubquery *>(ast.get()))
     {
-        /// Set unique aliases for all subqueries. This is needed, because content of subqueries could change after recursive analysis,
-        ///  and auto-generated column names could become incorrect.
+        /// Set unique aliases for all subqueries. This is needed, because:
+        /// 1) content of subqueries could change after recursive analysis, and auto-generated column names could become incorrect
+        /// 2) result of different scalar subqueries can be cached inside expressions compilation cache and must have different names
 
         if (subquery->alias.empty())
         {
-            size_t subquery_index = 1;
+            static std::atomic_uint64_t subquery_index = 1;
             while (true)
             {
-                alias = "_subquery" + toString(subquery_index);
-                if (!aliases.count("_subquery" + toString(subquery_index)))
+                alias = "_subquery" + std::to_string(subquery_index++);
+                if (!aliases.count(alias))
                     break;
-                ++subquery_index;
             }
 
             subquery->setAlias(alias);

dbms/tests/queries/0_stateless/00597_push_down_predicate.sql

@@ -23,7 +23,7 @@ SELECT * FROM (SELECT 1 AS id UNION ALL SELECT 2) WHERE id = 1;
 SELECT * FROM (SELECT arrayJoin([1, 2, 3]) AS id) WHERE id = 1;
 SELECT id FROM (SELECT arrayJoin([1, 2, 3]) AS id) WHERE id = 1;
 
-SELECT * FROM (SELECT 1 AS id, (SELECT 1)) WHERE _subquery1  = 1;
+SELECT * FROM (SELECT 1 AS id, (SELECT 1) as subquery) WHERE subquery = 1;
 SELECT * FROM (SELECT toUInt64(b) AS a, sum(id) AS b FROM test.test) WHERE a = 3;
 SELECT * FROM (SELECT toUInt64(b), sum(id) AS b FROM test.test) WHERE `toUInt64(sum(id))` = 3;
 SELECT date, id, name, value FROM (SELECT date, name, value, min(id) AS id FROM test.test GROUP BY date, name, value) WHERE id = 1;

dbms/tests/queries/0_stateless/00745_compile_scalar_subquery.reference

@@ -0,0 +1,2 @@
+1
+0

dbms/tests/queries/0_stateless/00745_compile_scalar_subquery.sql

@@ -0,0 +1,23 @@
+SET compile_expressions = 1;
+SET min_count_to_compile = 1;
+SET optimize_move_to_prewhere = 0;
+SET enable_optimize_predicate_expression=0;
+
+DROP TABLE IF EXISTS test.dt;
+DROP TABLE IF EXISTS test.testx;
+
+CREATE TABLE test.dt(tkey Int32) ENGINE = MergeTree order by tuple();
+INSERT INTO test.dt VALUES (300000);
+CREATE TABLE test.testx(t Int32, a UInt8) ENGINE = MergeTree ORDER BY tuple();
+INSERT INTO test.testx VALUES (100000, 0);
+
+SELECT COUNT(*) FROM test.testx WHERE NOT a AND t < (SELECT tkey FROM test.dt);
+
+DROP TABLE test.dt;
+CREATE TABLE test.dt(tkey Int32) ENGINE = MergeTree order by tuple();
+INSERT INTO test.dt VALUES (0);
+
+SELECT COUNT(*) FROM test.testx WHERE NOT a AND t < (SELECT tkey FROM test.dt);
+
+DROP TABLE IF EXISTS test.dt;
+DROP TABLE IF EXISTS test.testx;