MYSQL-刪改

刪除

delete：
DELETE [LOW_PRIORITY] [QUICK] [IGNORE] FROM tbl_name
[WHERE where_condition]
[ORDER BY ...]
[LIMIT row_count]

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注意：
需要的注意的是，一定要有限制條件，否則清空所有表數據
限制條件：
where
limit
刪除前請三思，確認表中數據無用，再ENTER

示例

刪除db1所有數據，相當於清空點db1表

delete from db1;

給定條件刪除數據，

delete from copy where age=100；

還可以先進行條件過濾，然後刪除指定的字段

delete from copy where age > 50 order by age desc limit 1;

修改

UPDATE [LOW_PRIORITY] [IGNORE] table_reference
SET col_name1={expr1|DEFAULT} [, col_name2={expr2|DEFAULT}] ...
[WHERE where_condition]
[ORDER BY ...]
[LIMIT row_count]

示例：

修改copy表中age 字段的值爲22,

update copy set age=22;

修改指定id號的name字段

update copy set name='hyt' where id=24;

修改指定id號的多個字段

updata copy set name='hyt',age='22' where id=13;

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請各位大佬多多指教