Add testcase for ANN index usage with subquery

docs/en/engines/table-engines/mergetree-family/annindexes.md

@@ -111,15 +111,16 @@ ANN indexes are built during column insertion and merge. As a result, `INSERT` a
 tables. ANNIndexes are ideally used only with immutable or rarely changed data, respectively when are far more read requests than write
 requests.
 
-ANN indexes support these queries:
+ANN indexes support this type of query:
 
-  ``` sql
-  SELECT *
-  FROM table
-  [WHERE ...]
-  ORDER BY Distance(vectors, Point)
-  LIMIT N
-  ```
+``` sql
+WITH [...] AS reference_vector
+SELECT *
+FROM table
+WHERE ...                       -- WHERE clause is optional
+ORDER BY Distance(vectors, reference_vector)
+LIMIT N
+```
 
 :::tip
 To avoid writing out large vectors, you can use [query

tests/queries/0_stateless/02354_vector_search_bugs.reference

@@ -4,3 +4,39 @@ It is possible to create parts with different Array vector sizes but there will
 Correctness of index with > 1 mark
 1	[1,0]	0
 9000	[9000,0]	0
+Issue #69085: Reference vector computed by a subquery
+Expression (Projection)
+  Limit (preliminary LIMIT (without OFFSET))
+    Sorting (Sorting for ORDER BY)
+      Expression (Before ORDER BY)
+        ReadFromMergeTree (default.tab)
+        Indexes:
+          PrimaryKey
+            Condition: true
+            Parts: 1/1
+            Granules: 4/4
+          Skip
+            Name: idx
+            Description: vector_similarity GRANULARITY 2
+            Parts: 1/1
+            Granules: 2/4
+Expression (Projection)
+  Limit (preliminary LIMIT (without OFFSET))
+    Sorting (Sorting for ORDER BY)
+      Expression (Before ORDER BY)
+        ReadFromMergeTree (default.tab)
+        Indexes:
+          PrimaryKey
+            Condition: true
+            Parts: 1/1
+            Granules: 4/4
+Expression (Projection)
+  Limit (preliminary LIMIT (without OFFSET))
+    Sorting (Sorting for ORDER BY)
+      Expression (Before ORDER BY)
+        ReadFromMergeTree (default.tab)
+        Indexes:
+          PrimaryKey
+            Condition: true
+            Parts: 1/1
+            Granules: 4/4

tests/queries/0_stateless/02354_vector_search_bugs.sql

@@ -53,3 +53,50 @@ ORDER BY L2Distance(vec, reference_vec)
 LIMIT 1;
 
 DROP TABLE tab;
+
+SELECT 'Issue #69085: Reference vector computed by a subquery';
+
+CREATE TABLE tab(id Int32, vec Array(Float32), INDEX idx vec TYPE vector_similarity('hnsw', 'cosineDistance', 'f16', 0, 0, 0) GRANULARITY 2) ENGINE = MergeTree ORDER BY id SETTINGS index_granularity = 3;
+INSERT INTO tab VALUES (0, [4.6, 2.3]), (1, [2.0, 3.2]), (2, [4.2, 3.4]), (3, [5.3, 2.9]), (4, [2.4, 5.2]), (5, [5.3, 2.3]), (6, [1.0, 9.3]), (7, [5.5, 4.7]), (8, [6.4, 3.5]), (9, [5.3, 2.5]), (10, [6.4, 3.4]), (11, [6.4, 3.2]);
+
+-- works
+EXPLAIN indexes = 1
+WITH [0., 2.] AS reference_vec
+SELECT
+    id,
+    vec,
+    cosineDistance(vec, reference_vec) AS distance
+FROM tab
+ORDER BY distance
+LIMIT 1
+SETTINGS enable_analyzer = 0;
+
+-- does not work
+EXPLAIN indexes = 1
+WITH (
+    SELECT vec
+    FROM tab
+    LIMIT 1
+) AS reference_vec
+SELECT
+    id,
+    vec,
+    cosineDistance(vec, reference_vec) AS distance
+FROM tab
+ORDER BY distance
+LIMIT 1
+SETTINGS enable_analyzer = 0;
+
+-- does not work as well
+EXPLAIN indexes = 1
+WITH (
+    SELECT [0., 2.]
+) AS reference_vec
+SELECT
+    id,
+    vec,
+    cosineDistance(vec, reference_vec) AS distance
+FROM tab
+ORDER BY distance
+LIMIT 1
+SETTINGS enable_analyzer = 0;