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

MySQL databaseKodi mungafunse bwanji zomwe zili patebulo?Ndemanga Yamafunso / Lamulo / Syntax

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

Kugwiritsa ntchito PHP mysqli_query() ndi SQL SELECT lamula kuti upeze deta.

Ntchitoyi imagwiritsidwa ntchito pochita malamulo a SQL ndikudutsa ntchito za PHP mysqli_fetch_array() kugwiritsa ntchito kapena kutulutsa deta pamafunso onse.

mysqli_fetch_array() Ntchitoyi imatenga mzere kuchokera pazotsatira zomwe zakhazikitsidwa ngati gulu logwirizana, kapena mndandanda wa manambala, kapena zonse ziwiri. Imabwezeranso mndandanda wopangidwa kuchokera ku mizere yotengedwa kuchokera pazotsatira, kapena zabodza ngati palibe mizere ina.

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.

Chidziwitso:Kumbukirani kuti ngati mukufuna kugwiritsa ntchito chosinthika mu chingwe, ikani chosinthikacho muzitsulo zopotanata.

Mu chitsanzo pamwambapa, gawo lachiwiri la PHP mysqli_fetch_array() ntchito ndi MYSQL_ASSOC, khazikitsani parameter iyi kuti mufunse zotsatira kuti mubwezere mndandanda wamagulu, mutha kugwiritsa ntchito dzina lamunda ngati index ya gululo.

PHP imapereka ntchito ina mysqli_fetch_assoc(), ntchitoyi imatenga mzere kuchokera pazotsatira zomwe zakhazikitsidwa ngati gulu lophatikizana.Imabweza gulu lophatikizana lopangidwa kuchokera mumizere yotengedwa kuchokera pazotsatira, kapena zabodza ngati palibe mizere ina.

Chitsanzo

Yesani chitsanzo chotsatirachi, chomwe chimagwiritsa ntchito mysqli_fetch_assoc() gwiritsani ntchito kutulutsa zolemba zonse za tebulo la data 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

Zitsanzo zotsatirazi zikugwiritsidwa ntchito MYSQL_NUM Gawoli likuwonetsa 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_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);
?>