CreateQuery x1 (children 3)
 Identifier x1
 Columns definition (children 1)
  ExpressionList (children 1)
   ColumnDeclaration i (children 1)
    DataType Nullable (children 1)
     ExpressionList (children 1)
      DataType int
 Storage definition (children 4)
  Function MergeTree
  Identifier i
  StorageOrderByElement (children 1)
   Identifier i
  Set
