Explain EXPLAIN SYNTAX (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 3)
    ExpressionList (children 2)
     Identifier key
     Identifier a
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       TableIdentifier test
    ExpressionList (children 2)
     OrderByElement (children 1)
      Identifier key
     OrderByElement (children 1)
      Function exp (children 1)
       ExpressionList (children 1)
        Function plus (children 1)
         ExpressionList (children 2)
          Identifier key
          Identifier a
