SQL MID() 使用实例教程
mid（ ）函数
mid（ ）函数是用来提取字符的文本字段。
数据库mid（ ）语法
SELECT MID(column_name,start[,length]) FROM table_name
| Parameter | Description |
|---|
| column_name | Required. The field to extract characters from. |
| start | Required. Specifies the starting position (starts at 1). |
| length | Optional. The number of characters to return. If omitted, the MID() function returns the rest of the text. |
来看个实例吧.
| | LastName | FirstName | Address | City |
|---|
| 1 | Hansen | Ola | Timoteivn 10 | Sandnes |
| 2 | Svendson | Tove | Borgvn 23 | Sandnes |
| 3 | Pettersen | Kari | Storgt 20 | Stavanger |
现在，我们要提取的前四个字符的“城市”专栏以上。
我们使用下面的SELECT语句：
SELECT MID(City,1,4) as SmallCity FROM Persons
结果.
