From b2377c3fefe8951158de201ea399485f6805f955 Mon Sep 17 00:00:00 2001
From: vdimir <vdimir@clickhouse.com>
Date: Tue, 7 May 2024 15:31:35 +0000
Subject: [PATCH] Fix mysql dictionary source

---
 src/Dictionaries/ExternalQueryBuilder.cpp     |  2 +-
 .../test_dictionaries_mysql/test.py           | 38 ++++++++++++++++++-
 2 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/src/Dictionaries/ExternalQueryBuilder.cpp b/src/Dictionaries/ExternalQueryBuilder.cpp
index 792c4e3e9074..a31301cd0f3b 100644
--- a/src/Dictionaries/ExternalQueryBuilder.cpp
+++ b/src/Dictionaries/ExternalQueryBuilder.cpp
@@ -401,7 +401,7 @@ std::string ExternalQueryBuilder::composeLoadKeysQuery(
         {
             writeString("SELECT * FROM (", out);
             writeString(query, out);
-            writeString(") WHERE ", out);
+            writeString(") AS subquery WHERE ", out);
             composeKeysCondition(key_columns, requested_rows, method, partition_key_prefix, out);
             writeString(";", out);
 
diff --git a/tests/integration/test_dictionaries_mysql/test.py b/tests/integration/test_dictionaries_mysql/test.py
index 360456b20460..332f4ca11bb9 100644
--- a/tests/integration/test_dictionaries_mysql/test.py
+++ b/tests/integration/test_dictionaries_mysql/test.py
@@ -76,7 +76,7 @@ def test_mysql_dictionaries_custom_query_full_load(started_cluster):
 
     query = instance.query
     query(
-        """
+        f"""
     CREATE DICTIONARY test_dictionary_custom_query
     (
         id UInt64,
@@ -95,12 +95,46 @@ def test_mysql_dictionaries_custom_query_full_load(started_cluster):
     """
     )
 
-    result = query("SELECT id, value_1, value_2 FROM test_dictionary_custom_query")
+    result = query(
+        "SELECT dictGetString('test_dictionary_custom_query', 'value_1', toUInt64(1))"
+    )
+    assert result == "Value_1\n"
 
+    result = query("SELECT id, value_1, value_2 FROM test_dictionary_custom_query")
     assert result == "1\tValue_1\tValue_2\n"
 
     query("DROP DICTIONARY test_dictionary_custom_query;")
 
+    query(
+        f"""
+    CREATE DICTIONARY test_cache_dictionary_custom_query
+    (
+        id1 UInt64,
+        id2 UInt64,
+        value_concat String
+    )
+    PRIMARY KEY id1, id2
+    LAYOUT(COMPLEX_KEY_CACHE(SIZE_IN_CELLS 10))
+    SOURCE(MYSQL(
+        HOST 'mysql80'
+        PORT 3306
+        USER 'root'
+        PASSWORD 'clickhouse'
+        QUERY 'SELECT id AS id1, id + 1 AS id2, CONCAT_WS(" ", "The", value_1) AS value_concat FROM test.test_table_1'))
+    LIFETIME(0)
+    """
+    )
+
+    result = query(
+        "SELECT dictGetString('test_cache_dictionary_custom_query', 'value_concat', (1, 2))"
+    )
+    assert result == "The Value_1\n"
+
+    result = query("SELECT id1, value_concat FROM test_cache_dictionary_custom_query")
+    assert result == "1\tThe Value_1\n"
+
+    query("DROP DICTIONARY test_cache_dictionary_custom_query;")
+
     execute_mysql_query(mysql_connection, "DROP TABLE test.test_table_1;")
     execute_mysql_query(mysql_connection, "DROP TABLE test.test_table_2;")