From f2c3000a93e70d3eb6994a79bfccc84c5ba275e4 Mon Sep 17 00:00:00 2001
From: Nikolay Degterinsky <evillique@gmail.com>
Date: Wed, 9 Aug 2023 21:40:06 +0000
Subject: [PATCH] Improve exception in ALTER query

---
 src/Storages/MergeTree/MergeTreeData.cpp                  | 4 ++++
 tests/queries/0_stateless/02834_alter_exception.reference | 0
 tests/queries/0_stateless/02834_alter_exception.sql       | 4 ++++
 3 files changed, 8 insertions(+)
 create mode 100644 tests/queries/0_stateless/02834_alter_exception.reference
 create mode 100644 tests/queries/0_stateless/02834_alter_exception.sql

diff --git a/src/Storages/MergeTree/MergeTreeData.cpp b/src/Storages/MergeTree/MergeTreeData.cpp
index 6179c70ca57..8938a3b6fbd 100644
--- a/src/Storages/MergeTree/MergeTreeData.cpp
+++ b/src/Storages/MergeTree/MergeTreeData.cpp
@@ -3166,6 +3166,10 @@ void MergeTreeData::checkAlterIsPossible(const AlterCommands & commands, Context
             }
         }
 
+        if (command.type == AlterCommand::MODIFY_QUERY)
+            throw Exception(ErrorCodes::NOT_IMPLEMENTED,
+                            "ALTER MODIFY QUERY is not supported by MergeTree engines family");
+
         if (command.type == AlterCommand::MODIFY_ORDER_BY && !is_custom_partitioned)
         {
             throw Exception(ErrorCodes::BAD_ARGUMENTS,
diff --git a/tests/queries/0_stateless/02834_alter_exception.reference b/tests/queries/0_stateless/02834_alter_exception.reference
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/tests/queries/0_stateless/02834_alter_exception.sql b/tests/queries/0_stateless/02834_alter_exception.sql
new file mode 100644
index 00000000000..d42f40fcbf7
--- /dev/null
+++ b/tests/queries/0_stateless/02834_alter_exception.sql
@@ -0,0 +1,4 @@
+DROP TABLE IF EXISTS alter_02834;
+CREATE TABLE alter_02834 (a UInt64) ENGINE=MergeTree() ORDER BY a;
+ALTER TABLE alter_02834 MODIFY QUERY SELECT a FROM alter_02834; -- { serverError NOT_IMPLEMENTED }
+DROP TABLE alter_02834;