update README

Author: PNixx

README.md

@@ -202,6 +202,39 @@ User.window('x', order: 'date', partition: 'name', rows: 'UNBOUNDED PRECEDING').
 #=> #<ActiveRecord::Relation [#<User *** >]>
 ```
 
+### CTE and CSE examples
+
+For activation CSE ([Common Scalar Expressions](https://clickhouse.com/docs/sql-reference/statements/select/with#common-scalar-expressions)) in ClickHouse `value` in hash must be a `Symbol` class.
+`key` in a hash must be converting to:
+
+* `String` -> quoted string
+* `Symbol` -> raw data
+* `Relation` -> sql query
+
+See in examples:
+
+```ruby
+# CTE
+Action.with(t: ActionView.where(event_name: 'test')).where(event_name: Action.from('t').select('event_name'))
+# Clickhouse (10.3ms)  WITH t AS (SELECT action_view.* FROM action_view WHERE action_view.event_name = \'test\') SELECT actions.* FROM actions WHERE actions.event_name IN (SELECT event_name FROM t)
+#=> #<ActiveRecord::Relation [#<Action *** >]>
+
+# CSE with string key
+Action.with('2026-01-01 15:23:00' => :t).where(Arel.sql('date = toDate(t)'))
+# Clickhouse (10.3ms)  WITH '2026-01-01 15:23:00' AS t SELECT actions.* FROM actions WHERE (date = toDate(t))
+#=> #<ActiveRecord::Relation [#<Action *** >]>
+
+# CSE with symbol key
+Action.with('(id, extension) -> concat(lower(id), extension)': :t).where(Arel.sql('date = toDate(t)'))
+# Clickhouse (10.3ms)  WITH (id, extension) -> concat(lower(id), extension) AS t SELECT actions.* FROM actions WHERE (date = toDate(t))
+#=> #<ActiveRecord::Relation [#<Action *** >]>
+
+# CSE with ActiveRecord relation key
+Action.with(ActionView.select(Arel.sql('min(date)')) => :min_date).where(Arel.sql('date = min_date'))
+# Clickhouse (10.3ms)  WITH (SELECT min(date) FROM action_view) AS min_date SELECT actions.* FROM actions WHERE (date = min_date)
+#=> #<ActiveRecord::Relation [#<Action *** >]>
+```
+
 
 ### Migration Data Types
 

spec/single/model_spec.rb

@@ -470,13 +470,13 @@ class ModelPk < ActiveRecord::Base
 
     describe '#cte & cse:' do
       it 'cte string' do
-        sql = Model.with('t' => ModelJoin.where(event_name: 'test')).where(event_name: Model.from('f').select('event_name')).to_sql
-        expect(sql).to eq('WITH t AS (SELECT joins.* FROM joins WHERE joins.event_name = \'test\') SELECT sample.* FROM sample WHERE sample.event_name IN (SELECT event_name FROM f)')
+        sql = Model.with('t' => ModelJoin.where(event_name: 'test')).where(event_name: Model.from('t').select('event_name')).to_sql
+        expect(sql).to eq('WITH t AS (SELECT joins.* FROM joins WHERE joins.event_name = \'test\') SELECT sample.* FROM sample WHERE sample.event_name IN (SELECT event_name FROM t)')
       end
 
       it 'cte symbol' do
-        sql = Model.with(t: ModelJoin.where(event_name: 'test')).where(event_name: Model.from('f').select('event_name')).to_sql
-        expect(sql).to eq('WITH t AS (SELECT joins.* FROM joins WHERE joins.event_name = \'test\') SELECT sample.* FROM sample WHERE sample.event_name IN (SELECT event_name FROM f)')
+        sql = Model.with(t: ModelJoin.where(event_name: 'test')).where(event_name: Model.from('t').select('event_name')).to_sql
+        expect(sql).to eq('WITH t AS (SELECT joins.* FROM joins WHERE joins.event_name = \'test\') SELECT sample.* FROM sample WHERE sample.event_name IN (SELECT event_name FROM t)')
       end
 
       it 'cse string variable' do