在PHP中,我们可以以多种方式添加字符串。
上述方法中哪个是最佳方法?还有其他方法可以获得更好的性能吗?
Method 1
----------------------------
$sql = "SELECT field1, ";
$sql .= " field2, ";
$sql .= " field3, ";
$sql .= " field4, ";
$sql .= "FROM table1 ";
$sql .= "WHERE condition1 = '".$value."' " ;
Method 2
----------------------------
$sql = 'SELECT field1, ';
$sql .= ' field2, ';
$sql .= ' field3, ';
$sql .= ' field4, ';
$sql .= 'FROM table1 ';
$sql .= 'WHERE condition1 = "'.$value.'" ' ;
Method 3
----------------------------
$sql = 'SELECT field1,
field2,
field3,
field4,
FROM table1
WHERE condition1 = "'.$value.'" ' ;
Method 4
----------------------------
$str = <<<HEREDOC
SELECT field1,
field2,
field3,
field4,
FROM table1
WHERE condition1 = "$value"
HEREDOC;
上述方法中哪个是最佳方法?还有其他方法可以获得更好的性能吗?