如何更改 MySQL 中项目顺序?
要更改 MySQL 中项目的顺序,请使用 ORDER BY 别名名称。我们首先创建一个表 -
mysql> create table DemoTable653 (Product1Amount int,Product2Amount int); Query OK, 0 rows affected (0.42 sec)
使用插入命令插入一些记录到表中 -
mysql> insert into DemoTable653 values(400,250); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable653 values(500,300); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable653 values(40,400); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable653 values(200,450); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable653 values(50,20); Query OK, 1 row affected (0.10 sec)
使用 select 语句从表中显示所有记录 -
mysql> select *from DemoTable653;
这将生成以下输出 -
+----------------+----------------+ | Product1Amount | Product2Amount | +----------------+----------------+ | 400 | 250 | | 500 | 300 | | 40 | 400 | | 200 | 450 | | 50 | 20 | +----------------+----------------+ 5 rows in set (0.00 sec)
以下是更改项目顺序并显示差异的查询 -
mysql> select Product1Amount,Product2Amount,(Product1Amount-Product2Amount) as ProductAmountDifference from DemoTable653 order by ProductAmountDifference;
这将生成以下输出 -
+----------------+----------------+-------------------------+ | Product1Amount | Product2Amount | ProductAmountDifference | +----------------+----------------+-------------------------+ | 40 | 400 | -360 | | 200 | 450 | -250 | | 50 | 20 | 30 | | 400 | 250 | 150 | | 500 | 300 | 200 | +----------------+----------------+-------------------------+ 5 rows in set (0.29 sec)
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