在 MySQL 中實現自定義排序順序
要在 MySQL 中實現自定義排序順序,你需要使用 ORDER BY FIELD()。我們首先建立一個表,程式碼如下 −
mysql> create table DemoTable -> ( -> Designation varchar(100) -> ); Query OK, 0 rows affected (1.65 sec)
使用 insert 命令向表中插入一些記錄,程式碼如下 −
mysql> insert into DemoTable values('Software Engineer'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('Associate Software Engineer'); Query OK, 1 row affected (0.25 sec) mysql> insert into DemoTable values('Software Development Engineer'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values('Product Manager'); Query OK, 1 row affected (0.17 sec)
使用 select 語句顯示錶中的所有記錄,程式碼如下 −
mysql> select *from DemoTable;
這會生成以下輸出 −
+-------------------------------+ | Designation | +-------------------------------+ | Software Engineer | | Associate Software Engineer | | Software Development Engineer | | Product Manager | +-------------------------------+ 4 rows in set (0.00 sec)
以下是實現 MySQL 中自定義排序順序的查詢 −
mysql> select *from DemoTable -> order by field(Designation,'Associate Software Engineer','Software Engineer','Software Development Engineer','Product Manager');
這會生成以下輸出 −
+-------------------------------+ | Designation | +-------------------------------+ | Associate Software Engineer | | Software Engineer | | Software Development Engineer | | Product Manager | +-------------------------------+ 4 rows in set (0.02 sec)
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