SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function arrayJoin (children 1)
     ExpressionList (children 1)
      Function splitByChar (children 1)
       ExpressionList (children 2)
        Literal \',\'
        Function toLowCardinality (children 1)
         ExpressionList (children 1)
          Literal \'a,b,c\'
