MySQL 如何在 WHERE 子句中實現 OR 運算子?
當任何一個運算元為真時,OR 運算子給出真結果。現在讓我們看一個示例並建立一個表 −
mysql> create table DemoTable663(ClientId int,ClientName varchar(100),ClientAge int); Query OK, 0 rows affected (0.55 sec)
使用 insert 命令在表中插入一些記錄 −
mysql> insert into DemoTable663 values(100,'Chris',45); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable663 values(101,'Robert',29); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable663 values(102,'John',45); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable663 values(103,'Chris',35); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable663 values(104,'Sam',45); Query OK, 1 row affected (0.72 sec)
使用 select 語句從表中顯示所有記錄 −
mysql> select *from DemoTable663;
這將生成以下輸出 −
+----------+------------+-----------+ | ClientId | ClientName | ClientAge | +----------+------------+-----------+ | 100 | Chris | 45 | | 101 | Robert | 29 | | 102 | John | 45 | | 103 | Chris | 35 | | 104 | Sam | 45 | +----------+------------+-----------+ 5 rows in set (0.00 sec)
以下是實現 OR 運算子的查詢 −
mysql> select *from DemoTable663 where ClientName='Chris' OR ClientAge=45;
這將生成以下輸出 −
+----------+------------+-----------+ | ClientId | ClientName | ClientAge | +----------+------------+-----------+ | 100 | Chris | 45 | | 102 | John | 45 | | 103 | Chris | 35 | | 104 | Sam | 45 | +----------+------------+-----------+ 4 rows in set (0.00 sec)
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