当使用PHP在MySQL中编写查询时，它的适用性将基于MySQL本身进行检查。所以使用MySQL提供的默认日期和时间格式，即'YYYY-MM-DD'

例子：

ATE: YYYY-MM-DD

Example: 2019-01-28

DATETIME: YYYY-MM-DD HH:MI:SS

Example: 2019-01-28 23:50:30

TIMESTAMP: YYYY-MM-DD HH:MI:SS

Example: 2019-01-28 23:50:30

YEAR: YYYY or YY

用于创建DataBase的MySQL查询：

CREATE DATABASE Date_time_example;

示例1：用于创建数据库和表的PHP程序

$servername = "localhost";

$username = "root";

$password = "";

$dbname = "test";

// 创建连接

$conn = mysqli_connect( $servername, $username, $password, $dbname );

// 检查连接

if ( !$conn ) {

die("Connection failed: " . mysqli_connect_error());

}

// 创建表的SQL查询

$sql = "CREATE TABLE date_test (

id INT AUTO_INCREMENT PRIMARY KEY,

created_at DATETIME

)";

if (mysqli_query($conn, $sql)) {

echo "Table date_test created successfully";

} else {

echo "Error creating table: " . mysqli_error($conn);

}

// 关闭连接

mysqli_close($conn);

输出：

Table date_test created successfully

示例2：将日期插入表中的PHP程序。

$servername = "localhost";

$username = "root";

$password = "";

$dbname = "test";

// 创建连接

$conn = mysqli_connect( $servername, $username, $password, $dbname );

// 检查连接

if ( !$conn ) {

die("Connection failed: " . mysqli_connect_error());

}

// 用于向表中插入数据的SQL查询

$sql = "INSERT INTO date_test( created_at )

VALUES( '2019-01-28 12:39:16' );";

if (mysqli_query($conn, $sql)) {

echo "New record created successfully";

} else {

echo "Error: " . $sql . "

" . mysqli_error($conn);

}

// 关闭连接

mysqli_close($conn);

输出：

New record created successfully

示例3：此示例用于显示在2019-01-28上创建的行。使用以下查询显示结果。created_at列不仅包含日期，还包含时间。所以它会显示错误信息。

SELECT * FROM date_test WHERE DATE( created_at ) = '2019-01-28';

$servername = "localhost";

$username = "root";

$password = "";

$dbname = "test";

//创建连接

$conn = mysqli_connect( $servername, $username, $password, $dbname );

// 检查连接

if ( !$conn ) {

die("Connection failed: " . mysqli_connect_error());

}

//SQL查询

$sql = "SELECT * FROM date_test

WHERE DATE(created_at) = '2019-01-28'";

$result = mysqli_query( $conn, $sql );

if ($result) {

echo $result; //打印查询结果

}

else {

echo "Error: " . $sql . "

" . mysqli_error($conn);

}

// 关闭连接

mysqli_close($conn);

输出：

id created_at

1 2019-01-28 12:39:16

要从DATETIME值获取年，季度，月，周，日，小时，分钟和秒，请使用以下语句中显示的函数：

HOUR(@dt)，MINUTE(@dt)，SECOND(@dt) )，DAY(@dt)，WEEK(@dt)，MONTH(@dt)，QUARTER(@dt)，YEAR(@dt);