有没有办法让我不必在每个条件下编写完整查询？

Question

有没有办法让我不必在每个条件下编写完整查询？if($_GET['l'] == 1){    $num = $db -> query("SELECT * FROM text WHERE type = '' AND gg = '1'") -> num_rows;} elseif($_GET['l'] == 2){    $num = $db -> query("SELECT * FROM text WHERE type = '' AND gg = '2'") -> num_rows;} else {    $num = $db -> query("SELECT * FROM text WHERE type = ''") -> num_rows;}

Answer 1

很简单，声明一个变量并在变量中进行查询。

$query = "SELECT * FROM text WHERE type = ''";

if($_GET['l'] == 1){

    $query .= "  AND gg = '1'";

} 

elseif($_GET['l'] == 2){

    $query .= "  AND gg = '2'";

} 

else {

    $query .= " ";

}

    $num = $db -> query($query) -> num_rows;

希望这对你有帮助。