如何按順序維護 MySQL “IN” 查詢?
藉助 field 命令可以按順序維護 MySQL IN 查詢。語法如下 −
select *from yourTableName anyVariableName where anyVariableName.yourColumnName in(value1,value2,......N) order by field(anyVariableName.yourColumnName,value1,value2,......N);
為了實現上述語法,讓我們建立一個表 −
mysql> create table OrderInDemo −> ( −> Id int, −> Name varchar(100), −> Age int −> ); Query OK, 0 rows affected (1.24 sec)
現在讓我們在表中插入一些記錄。插入記錄的查詢如下 −
mysql> insert into OrderInDemo values(90,'David',23); Query OK, 1 row affected (0.10 sec) mysql> insert into OrderInDemo values(9,'Sam',24); Query OK, 1 row affected (0.59 sec) mysql> insert into OrderInDemo values(10,'Carol',19); Query OK, 1 row affected (0.25 sec) mysql> insert into OrderInDemo values(1,'John',26); Query OK, 1 row affected (0.42 sec) mysql> insert into OrderInDemo values(3,'Johnson',25); Query OK, 1 row affected (0.18 sec) mysql> insert into OrderInDemo values(2,'Ramit',20); Query OK, 1 row affected (0.18 sec)
藉助 select 語句顯示所有記錄。查詢如下 −
mysql> select *from OrderInDemo;
以下是輸出 −
+------+---------+------+ | Id | Name | Age | +------+---------+------+ | 90 | David | 23 | | 9 | Sam | 24 | | 10 | Carol | 19 | | 1 | John | 26 | | 3 | Johnson | 25 | | 2 | Ramit | 20 | +------+---------+------+ 6 rows in set (0.00 sec)
在開頭實現我們討論過的語法,按順序維護 MySQL IN 查詢。查詢如下 −
mysql> select *from OrderInDemo OD where OD.Id in(10,1,3) −> order by field(OD.Id,10,1,3);
以下是按查詢中提供的順序顯示結果的輸出 −
+------+---------+------+ | Id | Name | Age | +------+---------+------+ | 10 | Carol | 19 | | 1 | John | 26 | | 3 | Johnson | 25 | +------+---------+------+ 3 rows in set (0.00 sec)
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