SQL select语句中Order by 1的目的是什么?

时间:2010-08-10 00:15:34

标签: sql sql-order-by

我正在阅读一些旧的代码,并注意到有几个带有order by 1子句的视图。这取得了什么成果?

示例:

Create view v_payment_summary AS
SELECT A.PAYMENT_DATE,
       (SELECT SUM(paymentamount)
          FROM payment B
         WHERE PAYMENT_DATE = B.PAYMENT_DATE
           and SOME CONDITION) AS SUM_X,
       (SELECT SUM(paymentamount)
          FROM payment B
         WHERE PAYMENT_DATE = B.PAYMENT_DATE
           and SOME OTHER CONDITION) AS SUM_Y    
FROM payment A    
ORDER BY 1;

8 个答案:

答案 0 :(得分:160)

此:

ORDER BY 1

...被称为“序数” - 该数字代表基于SELECT子句中定义的列数的列。在您提供的查询中,它表示:

ORDER BY A.PAYMENT_DATE

这不是推荐的做法,因为:

  1. 这不明显/明确
  2. 如果列顺序发生更改,则查询仍然有效,因此您可能会冒险按照您不想要的内容进行排序

答案 1 :(得分:32)

当您使用基于集合的运算符时,这非常有用,例如联合

select cola
  from tablea
union
select colb
  from tableb
order by 1;

答案 2 :(得分:7)

我相信Oracle它意味着按列#1排序

答案 3 :(得分:6)

这将按返回的第一列对结果进行排序。在示例中,它将按payment_date排序。

答案 4 :(得分:5)

它只是意味着通过第一列查询结果对视图或表进行排序。

答案 5 :(得分:3)

如第一栏中的其他答案ORDER BY 1命令所述。

我遇到了另一个你可能会使用它的例子。我们有一些需要订购的查询选择相同的列。如果按以下Name排序,则会出现SQL错误。

SELECT Name, Name FROM Segment ORDER BY 1

答案 6 :(得分:-1)

另见:

http://www.techonthenet.com/sql/order_by.php

有关订购的说明。我学到了什么! :)

当我想在sql语句中添加不确定数量的过滤器时,我也曾使用过它。马虎我知道,但它确实有效。 :P

答案 7 :(得分:-1)

示例测试WAMP服务器数据库的示例: -

mysql> select * from user_privileges;

| GRANTEE            | TABLE_CATALOG | PRIVILEGE_TYPE          | IS_GRANTABLE |
   +--------------------+---------------+-------------------------+--------------+
| 'root'@'localhost' | def           | SELECT                  | YES          |
| 'root'@'localhost' | def           | INSERT                  | YES          |
| 'root'@'localhost' | def           | UPDATE                  | YES          |
| 'root'@'localhost' | def           | DELETE                  | YES          |
| 'root'@'localhost' | def           | CREATE                  | YES          |
| 'root'@'localhost' | def           | DROP                    | YES          |
| 'root'@'localhost' | def           | RELOAD                  | YES          |
| 'root'@'localhost' | def           | SHUTDOWN                | YES          |
| 'root'@'localhost' | def           | PROCESS                 | YES          |
| 'root'@'localhost' | def           | FILE                    | YES          |
| 'root'@'localhost' | def           | REFERENCES              | YES          |
| 'root'@'localhost' | def           | INDEX                   | YES          |
| 'root'@'localhost' | def           | ALTER                   | YES          |
| 'root'@'localhost' | def           | SHOW DATABASES          | YES          |
| 'root'@'localhost' | def           | SUPER                   | YES          |
| 'root'@'localhost' | def           | CREATE TEMPORARY TABLES | YES          |
| 'root'@'localhost' | def           | LOCK TABLES             | YES          |
| 'root'@'localhost' | def           | EXECUTE                 | YES          |
| 'root'@'localhost' | def           | REPLICATION SLAVE       | YES          |
| 'root'@'localhost' | def           | REPLICATION CLIENT      | YES          |
| 'root'@'localhost' | def           | CREATE VIEW             | YES          |
| 'root'@'localhost' | def           | SHOW VIEW               | YES          |
| 'root'@'localhost' | def           | CREATE ROUTINE          | YES          |
| 'root'@'localhost' | def           | ALTER ROUTINE           | YES          |
| 'root'@'localhost' | def           | CREATE USER             | YES          |
| 'root'@'localhost' | def           | EVENT                   | YES          |
| 'root'@'localhost' | def           | TRIGGER                 | YES          |
| 'root'@'localhost' | def           | CREATE TABLESPACE       | YES          |
| 'root'@'127.0.0.1' | def           | SELECT                  | YES          |
| 'root'@'127.0.0.1' | def           | INSERT                  | YES          |
| 'root'@'127.0.0.1' | def           | UPDATE                  | YES          |
| 'root'@'127.0.0.1' | def           | DELETE                  | YES          |
| 'root'@'127.0.0.1' | def           | CREATE                  | YES          |
| 'root'@'127.0.0.1' | def           | DROP                    | YES          |
| 'root'@'127.0.0.1' | def           | RELOAD                  | YES          |
| 'root'@'127.0.0.1' | def           | SHUTDOWN                | YES          |
| 'root'@'127.0.0.1' | def           | PROCESS                 | YES          |
| 'root'@'127.0.0.1' | def           | FILE                    | YES          |
| 'root'@'127.0.0.1' | def           | REFERENCES              | YES          |
| 'root'@'127.0.0.1' | def           | INDEX                   | YES          |
| 'root'@'127.0.0.1' | def           | ALTER                   | YES          |
| 'root'@'127.0.0.1' | def           | SHOW DATABASES          | YES          |
| 'root'@'127.0.0.1' | def           | SUPER                   | YES          |
| 'root'@'127.0.0.1' | def           | CREATE TEMPORARY TABLES | YES          |
| 'root'@'127.0.0.1' | def           | LOCK TABLES             | YES          |
| 'root'@'127.0.0.1' | def           | EXECUTE                 | YES          |
| 'root'@'127.0.0.1' | def           | REPLICATION SLAVE       | YES          |
| 'root'@'127.0.0.1' | def           | REPLICATION CLIENT      | YES          |
| 'root'@'127.0.0.1' | def           | CREATE VIEW             | YES          |
| 'root'@'127.0.0.1' | def           | SHOW VIEW               | YES          |
| 'root'@'127.0.0.1' | def           | CREATE ROUTINE          | YES          |
| 'root'@'127.0.0.1' | def           | ALTER ROUTINE           | YES          |
| 'root'@'127.0.0.1' | def           | CREATE USER             | YES          |
| 'root'@'127.0.0.1' | def           | EVENT                   | YES          |
| 'root'@'127.0.0.1' | def           | TRIGGER                 | YES          |
| 'root'@'127.0.0.1' | def           | CREATE TABLESPACE       | YES          |
| 'root'@'::1'       | def           | SELECT                  | YES          |
| 'root'@'::1'       | def           | INSERT                  | YES          |
| 'root'@'::1'       | def           | UPDATE                  | YES          |
| 'root'@'::1'       | def           | DELETE                  | YES          |
| 'root'@'::1'       | def           | CREATE                  | YES          |
| 'root'@'::1'       | def           | DROP                    | YES          |
| 'root'@'::1'       | def           | RELOAD                  | YES          |
| 'root'@'::1'       | def           | SHUTDOWN                | YES          |
| 'root'@'::1'       | def           | PROCESS                 | YES          |
| 'root'@'::1'       | def           | FILE                    | YES          |
| 'root'@'::1'       | def           | REFERENCES              | YES          |
| 'root'@'::1'       | def           | INDEX                   | YES          |
| 'root'@'::1'       | def           | ALTER                   | YES          |
| 'root'@'::1'       | def           | SHOW DATABASES          | YES          |
| 'root'@'::1'       | def           | SUPER                   | YES          |
| 'root'@'::1'       | def           | CREATE TEMPORARY TABLES | YES          |
| 'root'@'::1'       | def           | LOCK TABLES             | YES          |
| 'root'@'::1'       | def           | EXECUTE                 | YES          |
| 'root'@'::1'       | def           | REPLICATION SLAVE       | YES          |
| 'root'@'::1'       | def           | REPLICATION CLIENT      | YES          |
| 'root'@'::1'       | def           | CREATE VIEW             | YES          |
| 'root'@'::1'       | def           | SHOW VIEW               | YES          |
| 'root'@'::1'       | def           | CREATE ROUTINE          | YES          |
| 'root'@'::1'       | def           | ALTER ROUTINE           | YES          |
| 'root'@'::1'       | def           | CREATE USER             | YES          |
| 'root'@'::1'       | def           | EVENT                   | YES          |
| 'root'@'::1'       | def           | TRIGGER                 | YES          |
| 'root'@'::1'       | def           | CREATE TABLESPACE       | YES          |
| ''@'localhost'     | def           | USAGE                   | NO           |
+--------------------+---------------+-------------------------+--------------+
85 rows in set (0.00 sec)

如果给予额外的order by PRIVILEGE_TYPE或者可以给予order by 3。请注意第3列(PRIVILEGE_TYPE)按字母顺序排序。

mysql> select * from user_privileges order by PRIVILEGE_TYPE;
+--------------------+---------------+-------------------------+--------------+
| GRANTEE            | TABLE_CATALOG | PRIVILEGE_TYPE          | IS_GRANTABLE |
+--------------------+---------------+-------------------------+--------------+
| 'root'@'127.0.0.1' | def           | ALTER                   | YES          |
| 'root'@'::1'       | def           | ALTER                   | YES          |
| 'root'@'localhost' | def           | ALTER                   | YES          |
| 'root'@'::1'       | def           | ALTER ROUTINE           | YES          |
| 'root'@'localhost' | def           | ALTER ROUTINE           | YES          |
| 'root'@'127.0.0.1' | def           | ALTER ROUTINE           | YES          |
| 'root'@'127.0.0.1' | def           | CREATE                  | YES          |
| 'root'@'::1'       | def           | CREATE                  | YES          |
| 'root'@'localhost' | def           | CREATE                  | YES          |
| 'root'@'::1'       | def           | CREATE ROUTINE          | YES          |
| 'root'@'localhost' | def           | CREATE ROUTINE          | YES          |
| 'root'@'127.0.0.1' | def           | CREATE ROUTINE          | YES          |
| 'root'@'::1'       | def           | CREATE TABLESPACE       | YES          |
| 'root'@'localhost' | def           | CREATE TABLESPACE       | YES          |
| 'root'@'127.0.0.1' | def           | CREATE TABLESPACE       | YES          |
| 'root'@'::1'       | def           | CREATE TEMPORARY TABLES | YES          |
| 'root'@'localhost' | def           | CREATE TEMPORARY TABLES | YES          |
| 'root'@'127.0.0.1' | def           | CREATE TEMPORARY TABLES | YES          |
| 'root'@'localhost' | def           | CREATE USER             | YES          |
| 'root'@'127.0.0.1' | def           | CREATE USER             | YES          |
| 'root'@'::1'       | def           | CREATE USER             | YES          |
| 'root'@'localhost' | def           | CREATE VIEW             | YES          |
| 'root'@'127.0.0.1' | def           | CREATE VIEW             | YES          |
| 'root'@'::1'       | def           | CREATE VIEW             | YES          |
| 'root'@'127.0.0.1' | def           | DELETE                  | YES          |
| 'root'@'::1'       | def           | DELETE                  | YES          |
| 'root'@'localhost' | def           | DELETE                  | YES          |
| 'root'@'::1'       | def           | DROP                    | YES          |
| 'root'@'localhost' | def           | DROP                    | YES          |
| 'root'@'127.0.0.1' | def           | DROP                    | YES          |
| 'root'@'127.0.0.1' | def           | EVENT                   | YES          |
| 'root'@'::1'       | def           | EVENT                   | YES          |
| 'root'@'localhost' | def           | EVENT                   | YES          |
| 'root'@'127.0.0.1' | def           | EXECUTE                 | YES          |
| 'root'@'::1'       | def           | EXECUTE                 | YES          |
| 'root'@'localhost' | def           | EXECUTE                 | YES          |
| 'root'@'127.0.0.1' | def           | FILE                    | YES          |
| 'root'@'::1'       | def           | FILE                    | YES          |
| 'root'@'localhost' | def           | FILE                    | YES          |
| 'root'@'localhost' | def           | INDEX                   | YES          |
| 'root'@'127.0.0.1' | def           | INDEX                   | YES          |
| 'root'@'::1'       | def           | INDEX                   | YES          |
| 'root'@'::1'       | def           | INSERT                  | YES          |
| 'root'@'localhost' | def           | INSERT                  | YES          |
| 'root'@'127.0.0.1' | def           | INSERT                  | YES          |
| 'root'@'127.0.0.1' | def           | LOCK TABLES             | YES          |
| 'root'@'::1'       | def           | LOCK TABLES             | YES          |
| 'root'@'localhost' | def           | LOCK TABLES             | YES          |
| 'root'@'127.0.0.1' | def           | PROCESS                 | YES          |
| 'root'@'::1'       | def           | PROCESS                 | YES          |
| 'root'@'localhost' | def           | PROCESS                 | YES          |
| 'root'@'::1'       | def           | REFERENCES              | YES          |
| 'root'@'localhost' | def           | REFERENCES              | YES          |
| 'root'@'127.0.0.1' | def           | REFERENCES              | YES          |
| 'root'@'::1'       | def           | RELOAD                  | YES          |
| 'root'@'localhost' | def           | RELOAD                  | YES          |
| 'root'@'127.0.0.1' | def           | RELOAD                  | YES          |
| 'root'@'::1'       | def           | REPLICATION CLIENT      | YES          |
| 'root'@'localhost' | def           | REPLICATION CLIENT      | YES          |
| 'root'@'127.0.0.1' | def           | REPLICATION CLIENT      | YES          |
| 'root'@'::1'       | def           | REPLICATION SLAVE       | YES          |
| 'root'@'localhost' | def           | REPLICATION SLAVE       | YES          |
| 'root'@'127.0.0.1' | def           | REPLICATION SLAVE       | YES          |
| 'root'@'127.0.0.1' | def           | SELECT                  | YES          |
| 'root'@'::1'       | def           | SELECT                  | YES          |
| 'root'@'localhost' | def           | SELECT                  | YES          |
| 'root'@'127.0.0.1' | def           | SHOW DATABASES          |  YES          |
| 'root'@'::1'       | def           | SHOW DATABASES          | YES          |
| 'root'@'localhost' | def           | SHOW DATABASES          | YES          |
| 'root'@'127.0.0.1' | def           | SHOW VIEW               | YES          |
| 'root'@'::1'       | def           | SHOW VIEW               | YES          |
| 'root'@'localhost' | def           | SHOW VIEW               | YES          |
| 'root'@'localhost' | def           | SHUTDOWN                | YES          |
| 'root'@'127.0.0.1' | def           | SHUTDOWN                | YES          |
| 'root'@'::1'       | def           | SHUTDOWN                | YES          |
| 'root'@'::1'       | def           | SUPER                   | YES          |
| 'root'@'localhost' | def           | SUPER                   | YES          |
| 'root'@'127.0.0.1' | def           | SUPER                   | YES          |
| 'root'@'127.0.0.1' | def           | TRIGGER                 | YES          |
| 'root'@'::1'       | def           | TRIGGER                 | YES          |
| 'root'@'localhost' | def           | TRIGGER                 | YES          |
| 'root'@'::1'       | def           | UPDATE                  | YES          |
| 'root'@'localhost' | def           | UPDATE                  | YES          |
| 'root'@'127.0.0.1' | def           | UPDATE                  | YES          |
| ''@'localhost'     | def           | USAGE                   | NO           |     +--------------------+---------------+-------------------------+--------------+
85 rows in set (0.00 sec)

绝对是一个很长的答案和很多滚动。 此外,我努力将查询的输出传递给文本文件。 以下是如何在不使用恼人的into outfile事物 -

的情况下执行此操作
  发表E:/sqllogfile.txt;

完成后,停止记录 -

  开球;

希望它增加更多清晰度。