SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Asterisk
   TablesInSelectQuery (children 2)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier t1
    TablesInSelectQueryElement (children 2)
     TableExpression (children 1)
      TableIdentifier t2
     TableJoin (children 1)
      Function and (children 1)
       ExpressionList (children 2)
        Function equals (children 1)
         ExpressionList (children 2)
          Function equals (children 1)
           ExpressionList (children 2)
            Literal NULL
            Identifier t1.key
          Identifier t2.id
        Function equals (children 1)
         ExpressionList (children 2)
          Function equals (children 1)
           ExpressionList (children 2)
            Literal \'\'
            Identifier t1.key
          Identifier t2.id