Question

我是mySQL的新手，因此我只是在寻找一个非常简单的COUNT查询，我没有找到任何真正清晰的在线解释。

我要做的是

COUNT我的PASSENGER表中groupID = 0的行数，然后能够回显计数将返回的数值，我该怎么做？

Answer 1

像这样的东西

$query = "SELECT COUNT(*) c FROM PASSENGER WHERE groupID = 0;";
$result = mysql_query($query);
$row = mysql_fetch_assoc($result);
echo $row['c']; //Here is your count

Answer 2

//get result
$data = mysql_query("SELECT count(*) as total FROM PASSENGER WHERE groupID = 0");
$info = mysql_fetch_assoc($data);

//output result
echo "Rows found :" . $info["total"];

Answer 3

$query = "SELECT COUNT(*) as result FROM passenger WHERE groupID = 0";
$result = mysql_query($query);
$row = mysql_fetch_row($result);
echo "Number is: ", $row;

Answer 4

SELECT COUNT(*) FROM PASSENGER WHERE GROUPID = 0;

Answer 5

其他答案总结得很漂亮。只是想添加，如果您以后在脚本中实际需要乘客表中的数据，那么谨慎的做法是不要进行两次单独的调用以获取计数和数据。最好的方法是：

<?php
$query = "SELECT * FROM PASSENGER WHERE groupID=0";
$result = mysql_query($query);
$result_count = mysql_num_rows($result);
?>

与：SELECT PASSENGER.*, COUNT(*) as passenger_count FROM PASSENGER WHERE groupID=0

相对

如何回显COUNT个查询

5 个答案: