单个 MySQL 查询仅更新范围内的特定记录而不更新整个列
mysqlmysqli database更新于 2024/4/4 6:11:00
首先我们创建一个表 −
mysql> create table DemoTable ( Name varchar(40), Position int ); Query OK, 0 rows affected (1.17 sec)
使用 insert 插入命令在表中插入一些记录 −
mysql> insert into DemoTable values('Chris',90);
Query OK, 1 row affected (0.20 sec)
mysql> insert into DemoTable values('David',67);
Query OK, 1 row affected (0.18 sec)
mysql> insert into DemoTable values('Bob',55);
Query OK, 1 row affected (0.15 sec)
mysql> insert into DemoTable values('Sam',40);
Query OK, 1 row affected (0.15 sec)
使用 select 语句显示表中的所有记录 −
mysql> select *from DemoTable;
这将产生以下输出 −
+-------+----------+ | Name | Position | +-------+----------+ | Chris | 90 | | David | 67 | | Bob | 55 | | Sam | 40 | +-------+----------+ 4 rows in set (0.00 sec)
以下查询仅更新范围内的特定记录而不更新整个列 −
mysql> update DemoTable set Position=Position+10 where Position > 50 and Position < 90; Query OK, 2 rows affected (0.11 sec) Rows matched : 2 Changed : 2 Warnings : 0
让我们再次检查表记录 −
mysql> select *from DemoTable;
这将产生以下输出 −
+-------+----------+ | Name | Position | +-------+----------+ | Chris | 90 | | David | 77 | | Bob | 65 | | Sam | 40 | +-------+----------+ 4 rows in set (0.00 sec)
