Update
用途:
更新表中原有数据
语法:
UPDATE table_name SET column_name = new_value WHERE column_name = some_value |
例:
“Person”表中的原始数据:
LastName |
FirstName |
Address |
City |
Nilsen |
Fred |
Kirkegt 56 |
Stavanger |
Rasmussen |
|
Storgt 67 |
|
运行下面的SQL将Person表中LastName字段为”Rasmussen”的FirstName更新为”Nina”:
UPDATE Person SET FirstName = 'Nina' WHERE LastName = 'Rasmussen' |
更新后”Person”表中的数据为:
LastName |
FirstName |
Address |
City |
Nilsen |
Fred |
Kirkegt 56 |
Stavanger |
Rasmussen |
Nina |
Storgt 67 |
|
同样的,用UPDATE语句也可以同时更新多个字段:
UPDATE Person SET Address = 'Stien 12', City = 'Stavanger' WHERE LastName = 'Rasmussen' |
更新后”Person”表中的数据为:
LastName |
FirstName |
Address |
City |
Nilsen |
Fred |
Kirkegt 56 |
Stavanger |
Rasmussen |
Nina |
Stien 12 |
Stavanger |