-2
A
回答
4
我認爲這個數字,你需要這樣的事:
SELECT age, COUNT(*)
FROM your_table
GROUP BY age
ORDER BY age;
這個查詢會打印出年齡和每個年齡段的兒童人數。
0
在Mysql中,您可以執行以下sql命令:
「按年齡分別從兒童組中選擇count(nr_children)」;
或在PHP中:
$servername = "localhost";
$username = "username";
$password = "password";
// Create connection
$conn = new mysqli($servername, $username, $password);
// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
$sql = "select * from children group by age";
$children = $conn->query($sql);
$nr_child = mysqli_num_rows($children);
echo $nr_child;
你可以發佈你的表和您的查詢? – Saty
'按年齡選擇table_name組中的計數(*)「 –
'select age,count(*)from table_name group by age'(你在選擇時缺少年齡) – agold