Explain EXPLAIN SYNTAX (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 4)
    ExpressionList (children 1)
     Asterisk
    TablesInSelectQuery (children 2)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       TableIdentifier t1_00826 (alias x)
     TablesInSelectQueryElement (children 2)
      TableExpression (children 1)
       TableIdentifier t1_00826 (alias y)
      TableJoin
    Function and (children 1)
     ExpressionList (children 2)
      Function equals (children 1)
       ExpressionList (children 2)
        Identifier x.a
        Identifier y.a
      Function equals (children 1)
       ExpressionList (children 2)
        Identifier x.b
        Identifier y.b
    ExpressionList (children 1)
     OrderByElement (children 1)
      Identifier all
