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The SELECT statement is used to select data from a database.
选择语句[SELECT]是用来从一个数据库中选取数据的。
The SELECT statement is used to select data from a database.
选择语句[SELECT] 是用来从一个数据库中选取数据的。
SELECT column_name(s) FROM table_name |
Note: SQL statements are not case sensitive. SELECT is the same as select.
注意:SQL语句是“字母大小写不敏感”的语句(它不区分字母的大小写),即:“SELECT”和“select”是一样的。
To get PHP to execute the statement above we must use the mysql_query() function. This function is used to send a query or command to a MySQL connection.
在PHP内创建数据库,我们需要在mysql_query()函数内使用上述语句。这个函数是用来发送MySQL数据库连接建立的请求和指令的。
The following example selects all the data stored in the "Person" table (The * character selects all of the data in the table):
下面这个案例展示了如何从“Person”表中选择所有的数据(通配符“*”表示在表单中选择所有的数据):
<?php $con = mysql_connect("localhost","peter","abc123"); if (!$con) { die('Could not connect: ' . mysql_error()); } mysql_select_db("my_db", $con); $result = mysql_query("SELECT * FROM person"); while($row = mysql_fetch_array($result)) { echo $row['FirstName'] . " " . $row['LastName']; echo "<br />"; } mysql_close($con); ?> |
The example above stores the data returned by the mysql_query() function in the $result variable. Next, we use the mysql_fetch_array() function to return the first row from the recordset as an array. Each subsequent call to mysql_fetch_array() returns the next row in the recordset. The while loop loops through all the records in the recordset. To print the value of each row, we use the PHP $row variable ($row['FirstName'] and $row['LastName']).
上述案例储存了通过“$result”变量中的“mysql_query()”函数所返回的数据。接下来,我们使用“mysql_fetch_array()”函数将记录中的第一行记录以一个数组的形式返回;那么接下来,如果继续请求“mysql_fetch_array()”函数,那它将返回记录中的第二行,“while loop”语句循环显示了所有的记录。我们使用PHP “$row”变量($row['FirstName'] 和 $row['LastName'])来输出每一行得值。
The output of the code above will be:
上述代码的输出结果如下:
Peter Griffin Glenn Quagmire |
The following example selects the same data as the example above, but will display the data in an HTML table:
下面这个案例:选择了与上述案例相同的数据,并在HTML表格中显示这些数据:
<?php $con = mysql_connect("localhost","peter","abc123"); if (!$con) { die('Could not connect: ' . mysql_error()); } mysql_select_db("my_db", $con); $result = mysql_query("SELECT * FROM person"); echo "<table border='1'> <tr> <th>Firstname</th> <th>Lastname</th> </tr>"; while($row = mysql_fetch_array($result)) { echo "<tr>"; echo "<td>" . $row['FirstName'] . "</td>"; echo "<td>" . $row['LastName'] . "</td>"; echo "</tr>"; } echo "</table>"; mysql_close($con); ?> |
The output of the code above will be:
上述代码的输出结果如下:
Firstname | Lastname |
---|---|
Glenn | Quagmire |
Peter | Griffin |