CreateQuery t2 (children 3)
 Identifier t2
 Columns definition (children 2)
  ExpressionList (children 1)
   ColumnDeclaration conversation (children 1)
    DataType UInt64
  ExpressionList (children 1)
   Constraint (children 1)
    Function in (children 1)
     ExpressionList (children 2)
      Identifier conversation
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 2)
          ExpressionList (children 1)
           Identifier id
          TablesInSelectQuery (children 1)
           TablesInSelectQueryElement (children 1)
            TableExpression (children 1)
             TableIdentifier t1
 Storage definition (children 2)
  Function MergeTree
  Identifier conversation
