Explain EXPLAIN SYNTAX (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 3)
    ExpressionList (children 4)
     Identifier left_table.id
     Identifier val_left
     Identifier val_middle
     Identifier val_right
    TablesInSelectQuery (children 3)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       TableIdentifier left_table
     TablesInSelectQueryElement (children 2)
      TableExpression (children 1)
       TableIdentifier middle_table
      TableJoin (children 1)
       Function equals (children 1)
        ExpressionList (children 2)
         Identifier left_table.id
         Identifier middle_table.id
     TablesInSelectQueryElement (children 2)
      TableExpression (children 1)
       TableIdentifier right_table
      TableJoin (children 1)
       Function equals (children 1)
        ExpressionList (children 2)
         Identifier middle_table.id
         Identifier right_table.id
    ExpressionList (children 4)
     OrderByElement (children 1)
      Identifier left_table.id
     OrderByElement (children 1)
      Identifier val_left
     OrderByElement (children 1)
      Identifier val_middle
     OrderByElement (children 1)
      Identifier val_right