PHP变量传递在数据库调用中不起作用

Question

这可行。

function get_distinct_size_for_bracelets() { 
    $sql = "SELECT DISTINCT size FROM mytable WHERE id = 27 AND type='plastic' ORDER BY size"; 
} 

这并不工作，并停止PHP死了，没有错误报告。

function get_distinct_size_for_bracelets($myvalue) { 
    $sql = "SELECT DISTINCT size FROM mytable WHERE id = 27 AND type=".$myvalue." ORDER BY size"; 
} 

我已经尝试了一些配置，没有任何工作。

Answer 1

function get_distinct_size_for_bracelets($myvalue) { 
    $sql = "SELECT DISTINCT size FROM mytable WHERE id = 27 AND type='".$myvalue."' ORDER BY size"; 
} 

您仍然需要SQL查询中的单引号。

Answer 2

记得引用传递的值：

function get_distinct_size_for_bracelets($myvalue) 
{ 
$sql = "SELECT DISTINCT size FROM mytable WHERE id = 27 AND type=".$myvalue." ORDER BY size"; 
} 

应该是：

function get_distinct_size_for_bracelets($myvalue) 
{ 
$sql = "SELECT DISTINCT size FROM mytable WHERE id = 27 AND type='".$myvalue."' ORDER BY size"; 
} 

注意在type添加单引号。

Answer 3

你还需要单引号。所以

$sql = "SELECT DISTINCT size FROM mytable WHERE id = 27 AND type='".$myvalue."' ORDER BY size"; 

Answer 4

尝试

function get_distinct_size_for_bracelets($myvalue) { 
    $sql = "SELECT DISTINCT size FROM mytable WHERE id = 27 AND type='".$myvalue."' ORDER BY size"; 
} 

Answer 5

你不会逃避你的价值，你就忘了你的单引号，这会是我的猜测。请尝试：

function get_distinct_size_for_bracelets($myvalue) { 
    $query = sprintf("SELECT DISTINCT size FROM mytable WHERE id = 27 AND type='%s' ORDER BY size", 
     mysql_real_escape_string($myvalue)); 
} 

这可以让您将转义值传递到字符串中，而不是使用连接。

Answer 6

MySQL也有不同的数据类型。而strings需要用引号括起来太：

$sql = "SELECT DISTINCT size FROM mytable WHERE id = 27 AND type='".$myvalue."' ORDER BY size"; 

或者额外使用mysql_real_escape_string function的更好：

$sql = "SELECT DISTINCT size FROM mytable WHERE id = 27 AND type='".mysql_real_escape_string($myvalue)."' ORDER BY size";