AlterQuery  t0 (children 2)
 ExpressionList (children 1)
  AlterCommand UPDATE (children 2)
   Literal UInt64_1
   ExpressionList (children 1)
    Assignment c0 (children 1)
     Function exists (children 1)
      ExpressionList (children 1)
       Subquery (children 1)
        SelectWithUnionQuery (children 1)
         ExpressionList (children 1)
          SelectQuery (children 2)
           ExpressionList (children 1)
            Literal UInt64_1
           TablesInSelectQuery (children 2)
            TablesInSelectQueryElement (children 1)
             TableExpression (children 1)
              TableIdentifier t1
            TablesInSelectQueryElement (children 2)
             TableExpression (children 1)
              TableIdentifier t0
             TableJoin
 Identifier t0
