如何使用 MySQL 更新特定列中的所有條目,除單個值外?
若要在忽略單個值的情況下更新所有條目,你需要使用 IF()。
讓我們首先建立一張表 -
mysql> create table DemoTable736 ( CustomerId int NOT NULL AUTO_INCREMENT PRIMARY KEY, CustomerName varchar(100), isMarried boolean ); Query OK, 0 rows affected (0.53 sec)
使用 insert 命令在表中插入一些記錄 -
mysql> insert into DemoTable736(CustomerName,isMarried) values('Chris',0);
Query OK, 1 row affected (0.18 sec)
mysql> insert into DemoTable736(CustomerName,isMarried) values('Robert',0);
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable736(CustomerName,isMarried) values('David',0);
Query OK, 1 row affected (0.24 sec)
mysql> insert into DemoTable736(CustomerName,isMarried) values('Mike',0);
Query OK, 1 row affected (0.15 sec)
mysql> insert into DemoTable736(CustomerName,isMarried) values('Carol',1);
Query OK, 1 row affected (0.15 sec)
mysql> insert into DemoTable736(CustomerName,isMarried) values('Bob',0);
Query OK, 1 row affected (0.20 sec)使用 select 語句顯示錶中的所有記錄 −
mysql> select *from DemoTable736;
這將產生以下輸出 -
+------------+--------------+-----------+ | CustomerId | CustomerName | isMarried | +------------+--------------+-----------+ | 1 | Chris | 0 | | 2 | Robert | 0 | | 3 | David | 0 | | 4 | Mike | 0 | | 5 | Carol | 1 | | 6 | Bob | 0 | +------------+--------------+-----------+ 6 rows in set (0.00 sec)
以下是使用 MySQL 在特定列中更新除單個值以外的所有條目的查詢。這裡我們更新了 “isMarried” 列 -
mysql> update DemoTable736 set isMarried=if(CustomerId=5,1,1); Query OK, 5 rows affected (0.13 sec) Rows matched: 6 Changed: 5 Warnings: 0
讓我們再次檢查表記錄 −
mysql> select *from DemoTable736;
這將產生以下輸出 -
+------------+--------------+-----------+ | CustomerId | CustomerName | isMarried | +------------+--------------+-----------+ | 1 | Chris | 1 | | 2 | Robert | 1 | | 3 | David | 1 | | 4 | Mike | 1 | | 5 | Carol | 1 | | 6 | Bob | 1 | +------------+--------------+-----------+ 6 rows in set (0.00 sec)
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