使用數字對 MySQL 字串進行排序?
要對帶數字的 MySQL 字串排序,以下是語法,其中我們使用了 ORDER BY、SUBSTR() 和 CAST() −
SELECT *FROM yourTableName ORDER BY SUBSTR(yourColumnName FROM 1 FOR 2), CAST(SUBSTR(yourColumnName FROM 2) AS UNSIGNED);
要理解上述語法,讓我們建立一個表。建立表查詢如下 −
mysql> create table OrderByStringWithNumbers -> ( -> Id int NOT NULL AUTO_INCREMENT, -> Words varchar(10), -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.86 sec)
使用插入命令向表中插入一些記錄。查詢如下 −
mysql> insert into OrderByStringWithNumbers(Words) values('A10'); Query OK, 1 row affected (0.19 sec) mysql> insert into OrderByStringWithNumbers(Words) values('A30'); Query OK, 1 row affected (0.19 sec) mysql> insert into OrderByStringWithNumbers(Words) values('A12'); Query OK, 1 row affected (0.13 sec) mysql> insert into OrderByStringWithNumbers(Words) values('A11'); Query OK, 1 row affected (0.17 sec) mysql> insert into OrderByStringWithNumbers(Words) values('A28'); Query OK, 1 row affected (0.13 sec) mysql> insert into OrderByStringWithNumbers(Words) values('A21'); Query OK, 1 row affected (0.20 sec)
使用 select 語句從表中顯示所有記錄 −
mysql> select *from OrderByStringWithNumbers;
以下是輸出 −
+----+-------+ | Id | Words | +----+-------+ | 1 | A10 | | 2 | A30 | | 3 | A12 | | 4 | A11 | | 5 | A28 | | 6 | A21 | +----+-------+ 6 rows in set (0.00 sec)
以下是按帶數字的字串排序的查詢 −
mysql> select *from OrderByStringWithNumbers order by -> substr(Words from 1 for 2), -> cast(substr(Words from 2) AS UNSIGNED);
以下是輸出 −
+----+-------+ | Id | Words | +----+-------+ | 1 | A10 | | 4 | A11 | | 3 | A12 | | 6 | A21 | | 5 | A28 | | 2 | A30 | +----+-------+ 6 rows in set (0.00 sec)
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