SelectWithUnionQuery (children 2)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Function sum (children 1)
     ExpressionList (children 1)
      Function ignore (children 1)
       ExpressionList (children 1)
        Asterisk
   TablesInSelectQuery (children 2)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier t0 (alias a)
    TablesInSelectQueryElement (children 2)
     TableExpression (children 1)
      TableIdentifier t1 (alias b)
     TableJoin (children 1)
      Function equals (children 1)
       ExpressionList (children 2)
        Identifier a.x
        Identifier b.x
 Identifier Null
