SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 3)
    Identifier command
    Identifier is_done
    Identifier latest_fail_reason
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier system.mutations
   Function and (children 1)
    ExpressionList (children 2)
     Function equals (children 1)
      ExpressionList (children 2)
       Identifier database
       Function currentDatabase (children 1)
        ExpressionList
     Function equals (children 1)
      ExpressionList (children 2)
       Identifier table
       Literal \'t_block_number_delete\'
