Isalathiso senqaku
MySQLHlela ngemimandla emininzi?MySQL lungelelanisa ngokwehla ulandelelwano olunyukayo lwengxelo yombuzo/umsebenzi
Uhlobo lweMySQL
Siyazi ukusebenzisa ingxelo ye-SQL KHETHA ukufunda idatha kwitafile ye-MySQL.
Ukuba sifuna ukuhlela idatha efundiweyo, sinokusebenzisa i-MySQL's UKUQALA igatya ukuseta ukuba ngowuphi umhlaba kunye nendlela ofuna ukuhlela ngayo, kwaye emva koko ubuyisele iziphumo zophendlo.
Igrama
Oku kulandelayo yinkcazo ye-SQL KHETHA esebenzisa i-ORDER BY clause ukuhlela idatha yombuzo ngaphambi kokubuyisela idatha:
SELECT field1, field2,...fieldN table_name1, table_name2... ORDER BY field1, [field2...] [ASC [DESC]]
- Ungasebenzisa nawuphi na umhlaba njengemeko yokuhlela ukubuyisela iziphumo zombuzo ohleliweyo.
- Ungacwangcisa imihlaba emininzi ukumisa ngayo.
- Ungasebenzisa i-ASC okanye igama elingundoqo le-DESC ukuseta iziphumo zombuzo eziza kuhlelwa ngokwenyuka okanye ukwehla komyalelo. Ngokungagqibekanga, ihlelwa ngokolandelelwano olunyukayo.
- Unokongeza APHO...NJENGAMAGAtya ukuseta iimeko.
Ukusebenzisa i-ORDER BY gatya kwi-prompt yomyalelo
Oku kulandelayo kuya kusebenzisa i-ORDER BY clause kwi-SQL SELECT statement ukufunda idatha kwi-MySQL data table chenweiliang_tbl:
Umzekelo
Zama lo mzekelo ulandelayo kwaye iziphumo ziya kuhlelwa ngokwenyuka nokuhla.
SQL uhlobo
mysql> use chenweiliang; Database changed mysql> SELECT * from chenweiliang_tbl ORDER BY submission_date ASC; +-----------+---------------+---------------+-----------------+ | chenweiliang_id | chenweiliang_title | chenweiliang_author | submission_date | +-----------+---------------+---------------+-----------------+ | 3 | 学习 Java | chenweiliang.com | 2015-05-01 | | 4 | 学习 Python | chenweiliang.com | 2016-03-06 | | 1 | 学习 PHP | 陈沩亮博客 | 2017-04-12 | | 2 | 学习 MySQL | 陈沩亮博客 | 2017-04-12 | +-----------+---------------+---------------+-----------------+ 4 rows in set (0.01 sec) mysql> SELECT * from chenweiliang_tbl ORDER BY submission_date DESC; +-----------+---------------+---------------+-----------------+ | chenweiliang_id | chenweiliang_title | chenweiliang_author | submission_date | +-----------+---------------+---------------+-----------------+ | 1 | 学习 PHP | 陈沩亮博客 | 2017-04-12 | | 2 | 学习 MySQL | 陈沩亮博客 | 2017-04-12 | | 4 | 学习 Python | chenweiliang.com | 2016-03-06 | | 3 | 学习 Java | chenweiliang.com | 2015-05-01 | +-----------+---------------+---------------+-----------------+ 4 rows in set (0.01 sec)
Funda yonke idatha kwitheyibhile ye-chenweiliang_tbl kwaye uyihlele ngokunyuka komyalelo we-submission_date field.
Ukusebenzisa i-ORDER BY clause kwizikripti ze-PHP
Ungasebenzisa umsebenzi we-PHP mysqli_query () kunye nomyalelo ofanayo weSQL KHETHA ngo-ORDER BY gatya ukufumana idatha.
Lo msebenzi usetyenziselwa ukuphumeza imiyalelo yeSQL kwaye emva koko ukhuphe yonke idata ebuzwayo ngomsebenzi wePHP mysqli_fetch_array().
Umzekelo
Zama lo mzekelo ulandelayo.Idatha ebuziweyo ibuyiswa emva kokuhlelwa ngokwehla ngo-submission_date field.
I-MySQL i-ORDER ngovavanyo:
<?
php
$dbhost = 'localhost:3306'; // mysql服务器主机地址
$dbuser = 'root'; // mysql用户名
$dbpass = '123456'; // mysql用户名密码
$conn = mysqli_connect($dbhost, $dbuser, $dbpass);
if(! $conn )
{
die('连接失败: ' . mysqli_error($conn));
}
// 设置编码，防止中文乱码
mysqli_query($conn , "set names utf8");
$sql = 'SELECT chenweiliang_id, chenweiliang_title,
chenweiliang_author, submission_date
FROM chenweiliang_tbl
ORDER BY submission_date ASC';
mysqli_select_db( $conn, 'chenweiliang' );
$retval = mysqli_query( $conn, $sql );
if(! $retval )
{
die('无法读取数据: ' . mysqli_error($conn));
}
echo '<h2>陈沩亮博客 MySQL ORDER BY 测试<h2>';
echo '<table border="1"><tr><td>教程 ID</td><td>标题</td><td>作者</td><td>提交日期</td></tr>';
while($row = mysqli_fetch_array($retval, MYSQL_ASSOC))
{
echo "<tr><td> {$row['chenweiliang_id']}</td> ".
"<td>{$row['chenweiliang_title']} </td> ".
"<td>{$row['chenweiliang_author']} </td> ".
"<td>{$row['submission_date']} </td> ".
"</tr>";
}
echo '</table>';
mysqli_close($conn);
?>Ndiyathemba Chen Weiliang Blog ( https://www.chenweiliang.com/ ) ekwabelwanayo "Ukhetho lwemeko ye-MySQL emininzi? I-MySQL iodolo ngokuhla ulandelelwano olunyukayo lwengxelo yombuzo / umsebenzi", oluncedo kuwe.
Wamkelekile ukwabelana ngekhonkco leli nqaku:https://www.chenweiliang.com/cwl-476.html