CreateQuery b_customers (children 3)
 Identifier b_customers
 Columns definition (children 1)
  ExpressionList (children 2)
   ColumnDeclaration customer_id (children 1)
    DataType Int64
   ColumnDeclaration first_order_id (children 1)
    DataType Int64
 Storage definition (children 2)
  Function MergeTree
  Identifier customer_id
