Kodi MySQL database imafunsa bwanji patebulo?Ndemanga Yamafunso / Lamulo / Syntax

Kodi mungafufuze bwanji deta kuchokera patebulo mu database ya MySQL?

MySQL Funso zambiri

Ma database a MySQL amagwiritsa ntchito mawu a SQL SELECT kuti afunse zambiri.

Mutha kufunsa zambiri mu database kudzera pa mysql> command prompt window, kapena kudzera mu PHP script.

galamala

Zotsatirazi ndizomwe zimapangidwira SELECT pakufunsa deta mu database ya MySQL:

SELECT column_name,column_name
FROM table_name
[WHERE Clause]
[OFFSET M ][LIMIT N]

• M'mafunso, mutha kugwiritsa ntchito tebulo limodzi kapena angapo, kulekanitsa matebulo ndi koma (,), ndikugwiritsa ntchito mawu akuti WHERE kuti muyike mikhalidwe yamafunso.
• Lamulo la SELECT limatha kuwerenga mbiri imodzi kapena zingapo.
• Mutha kugwiritsa ntchito asterisk (*) kuti musinthe magawo ena, mawu akuti SELECT adzabwezera zonse zomwe zili patebulo.
• Mutha kugwiritsa ntchito mawu akuti WHERE kuphatikiza chikhalidwe chilichonse.
• Mutha kufotokozera momwe mungasinthire deta pomwe mawu a SELECT amayamba kufunsa ndi OFFSET.Mwachikhazikitso, kuchepetsa ndi 0.
• Mutha kugwiritsa ntchito katundu wa LIMIT kuti muyike kuchuluka kwa ma rekodi omwe abwezedwa.

Pezani data kudzera pa Command Prompt

Muchitsanzo chotsatirachi, tidzagwiritsa ntchito lamulo la SQL SELECT kuti tipeze deta ya MySQL data table chenweiliang_tbl:

Chitsanzo

Chitsanzo chotsatirachi chibwezera zolembedwa zonse za tebulo la chenweiliang_tbl:

select * from chenweiliang_tbl;

Gwiritsani ntchito zolemba za PHP kuti mupeze deta

Gwiritsani ntchito ntchito ya PHP ya mysqli_query() ndi lamulo la SQL SELECT kuti mupeze deta.

Ntchitoyi imagwiritsidwa ntchito pochita malamulo a SQL, kenako ntchito ya PHP mysqli_fetch_array() imagwiritsidwa ntchito kupeza kapena kutulutsa deta yonse yomwe yafunsidwa.

Ntchito ya mysqli_fetch_array() imatenga mzere kuchokera ku zotsatira zomwe zasankhidwa ngati gulu logwirizana, gulu la manambala, kapena zonse ziwiri, ndipo imabweza gulu lomwe lapangidwa kuchokera ku mzere womwe watengedwa kuchokera ku gulu la zotsatira. Ngati palibe mizere ina, imabweza zabodza.

Chitsanzo chotsatirachi chikuwerenga zolemba zonse kuchokera pa tebulo la chenweiliang_tbl.

Chitsanzo

Yesani chitsanzo chotsatirachi kuti muwonetse zolemba zonse za tebulo la chenweiliang_tbl.

<?
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';
 
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 mysqli_fetch_array 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);
?>

Mu chitsanzo chapamwamba, mzere uliwonse wa zolemba zomwe zimawerengedwa zimaperekedwa ku kusintha kwa $ mzere, ndiyeno mtengo uliwonse umasindikizidwa.

Zindikirani: Kumbukirani kuyika chosinthikacho mu ma braces opindika ngati mukufuna kuchigwiritsa ntchito mu chingwe.

Mu chitsanzo pamwambapa, gawo lachiwiri la ntchito ya PHP mysqli_fetch_array() ndi MYSQL_ASSOC . Kukhazikitsa gawoli kumabwezera gulu logwirizana, ndipo mutha kugwiritsa ntchito dzina la munda ngati index ya gulu.

PHP imapereka ntchito ina, `mysqli_fetch_assoc()` , yomwe imatenga mzere umodzi kuchokera ku zotsatira zomwe zasankhidwa ngati gulu logwirizana. Imabwezera gulu logwirizana kutengera mzere womwe watengedwa kuchokera ku gulu lotsatira; ngati palibe mizere ina, imabwezera zabodza.

Chitsanzo

Yesani chitsanzo chotsatirachi, chomwe chimagwiritsa ntchito ntchito ya mysqli_fetch_assoc() kuti itulutse zolemba zonse za tebulo la chenweiliang_tbl:

<?
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';
 
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 mysqli_fetch_assoc 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($row = mysqli_fetch_assoc($retval))
{
 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);
?>

Mutha kugwiritsanso ntchito MYSQL_NUM yosalekeza ngati gawo lachiwiri la PHP mysqli_fetch_array() ntchito, yomwe imabweretsa manambala angapo.

Chitsanzo

Chitsanzo chotsatirachi chikugwiritsa ntchito MYSQL_NUM parameter kuti iwonetse zolemba zonse mu tebulo la chenweiliang_tbl:

<?
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';
 
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 mysqli_fetch_array 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_NUM))
{
 echo "<tr><td> {$row[0]}</td> ".
 "<td>{$row[1]} </td> ".
 "<td>{$row[2]} </td> ".
 "<td>{$row[3]} </td> ".
 "</tr>";
}
echo '</table>';
mysqli_close($conn);
?>

kukumbukira kukumbukira

Ndimchitidwe wabwino kumasula kukumbukira kalozera titapanga mawu osankhidwa.

Memory imatha kutulutsidwa kudzera mu ntchito ya PHP mysqli_free_result().

Chitsanzo chotsatira chikuwonetsa kugwiritsa ntchito ntchitoyi.

Chitsanzo

Yesani zitsanzo zotsatirazi:

Kukumbukira kwaulere ndi mysqli_free_result:

<?
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';
 
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 mysqli_fetch_array 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_NUM))
{
 echo "<tr><td> {$row[0]}</td> ".
 "<td>{$row[1]} </td> ".
 "<td>{$row[2]} </td> ".
 "<td>{$row[3]} </td> ".
 "</tr>";
}
echo '</table>';
// 释放内存
mysqli_free_result($retval);
mysqli_close($conn);
?>