Select
用途：
从指定表中取出指定的列的数据
语法：
SELECT column_name(s) FROM table_name
例：
“Persons” 表中的数据有
| LastName | FirstName | Address | City |
| Hansen | Ola | Timoteivn 10 | Sandnes |
| Svendson | Tove | Borgvn 23 | Sandnes |
| Pettersen | Kari | Storgt 20 | Stavanger |
选出字段名” LastName”、” FirstName” 的数据
SELECT LastName,FirstName FROM Persons
返回结果:
| LastName | FirstName |
| Hansen | Ola |
| Svendson | Tove |
| Pettersen | Kari |
选出所有字段的数据
SELECT * FROM Persons
返回结果:
| LastName | FirstName | Address | City |
| Hansen | Ola | Timoteivn 10 | Sandnes |
| Svendson | Tove | Borgvn 23 | Sandnes |
| Pettersen | Kari | Storgt 20 | Stavanger |