AlterQuery  check_constraint (children 2)
 ExpressionList (children 1)
  AlterCommand ADD_CONSTRAINT (children 1)
   Constraint (children 1)
    Subquery (children 1)
     SelectWithUnionQuery (children 1)
      ExpressionList (children 1)
       SelectQuery (children 1)
        ExpressionList (children 1)
         Literal UInt64_1
 Identifier check_constraint
