CreateQuery middle_table (children 3)
 Identifier middle_table
 Columns definition (children 1)
  ExpressionList (children 2)
   ColumnDeclaration id (children 1)
    DataType UInt64
   ColumnDeclaration val_middle (children 1)
    DataType String
 Storage definition (children 2)
  Function MergeTree (children 1)
   ExpressionList
  Identifier id