Me pehea te paatai ​​​​raraunga patai a MySQL i roto i te ripanga?Tauākī Uiui/Whakahau/Wetereo

Me pēhea te uiui raraunga mai i tētahi ripanga i roto i tētahi pātengi raraunga MySQL ? Tauākī/whakahau/pūnaha uiui

MySQL Raraunga patai

Ka whakamahia e nga papaunga raraunga MySQL nga korero SQL SELECT ki te uiui raraunga.

Ka taea e koe te uiui i nga raraunga i roto i te paataka raraunga ma te mysql> matapihi whakahau whakahau, ma te tuhinga PHP ranei.

wetereo

E whai ake nei ko te wetereo SELECT whanui mo te uiui i nga raraunga i roto i te papanga raraunga MySQL:

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

• I roto i te tauākī uiui, ka taea e koe te whakamahi i tetahi ripanga, neke atu ranei, wehe i nga ripanga ki nga piko (,), ka whakamahi i te korero WHERE hei whakatakoto tikanga patai.
• Ka taea e te whakahau SELECT te panui kotahi, neke atu ranei nga rekoata.
• Ka taea e koe te whakamahi i te whetūriki (*) hei whakakapi i etahi atu mara, ma te tauākī SELECT ka whakahoki i nga raraunga āpure katoa o te ripanga
• Ka taea e koe te whakamahi i te korero WHERE hei whakauru i tetahi ahuatanga.
• Ka taea e koe te whakapūtā te whakawākanga raraunga i tīmata ai te tauākī SELECT i te uiui mā te OFFSET.Ma te taunoa ko te 0 te utu.
• Ka taea e koe te whakamahi i te taonga LIMIT hei tautuhi i te maha o nga rekoata i whakahokia.

Tikina raraunga ma te whakahau whakahau

I roto i te tauira e whai ake nei, ka whakamahia e matou te whakahau SQL SELECT ki te tiki raraunga o te ripanga raraunga MySQL chenweiliang_tbl:

Akoranga

Ko te tauira e whai ake nei ka whakahoki mai i nga rekoata katoa o te ripanga raraunga chenweiliang_tbl:

select * from chenweiliang_tbl;

Whakamahia te tuhinga PHP hei tiki raraunga

Whakamahia te mahi PHP mysqli_query() me te whakahau SQL SELECT hei tiki raraunga.

Ka whakamahia tēnei mahi hei whakahaere i ngā whakahau SQL, ā, ka whakamahia te mahi PHP mysqli_fetch_array() hei uru atu, hei whakaputa rānei i ngā raraunga katoa e pātaihia ana.

Ka tikina e te mahi mysqli_fetch_array() tētahi rarangi mai i te huinga hua hei huinga hononga, hei huinga tau, hei huinga rua rānei, ā, ka whakahokia mai he huinga i hangaia mai i te rarangi i tikina mai i te huinga hua. Mēnā kāore he rarangi atu, ka whakahokia mai he teka.

Ko te tauira e whai ake nei ka panui nga rekoata katoa mai i te ripanga raraunga chenweiliang_tbl.

Akoranga

Whakamātauria te tauira e whai ake nei hei whakaatu i nga rekoata katoa o te ripanga raraunga 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);
?>

I roto i te tauira i runga ake nei, ka tautapahia ia rarangi rekoata e panuitia ana ki te taurangi $rarangi, katahi ka taia ia uara.

Kia mahara: Kia maumahara ki te tāpiri i te taurangi ki roto i ngā whītiki miro mēnā me whakamahi i roto i te aho.

I te tauira i runga ake nei, ko te tawhā tuarua o te mahi PHP mysqli_fetch_array() ko MYSQL_ASSOC . Mā te whakatakoto i tēnei tawhā ka whakahokia mai he huinga hononga, ā, ka taea e koe te whakamahi i te ingoa o te āpure hei taupū mō te huinga.

Kei te PHP tētahi atu mahi, ko te `mysqli_fetch_assoc()` , e tiki ana i tētahi rarangi mai i te huinga hua hei huinga hononga. Ka whakahokia mai he huinga hononga i runga i ngā rarangi i tangohia mai i te huinga hua; ki te kore he rarangi e wātea ana, ka whakahokia mai he teka.

Akoranga

Whakamātauria te tauira e whai ake nei, e whakamahi ana i te mahi mysqli_fetch_assoc() hei whakaputa i ngā tuhinga katoa o te ripanga 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);
?>

Ka taea hoki e koe te whakamahi i te MYSQL_NUM tonu hei tawhā tuarua o te mahi PHP mysqli_fetch_array(), e whakahoki ana i te huinga tau.

Akoranga

Ko te tauira e whai ake nei e whakamahi ana i te tawhā MYSQL_NUM hei whakaatu i ngā tuhinga katoa i roto i te ripanga 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);
?>

tuku mahara

He mahi pai ki te whakawātea i te pūmahara pehu i muri i tā mātou mahi i tētahi tauākī SELECT.

Ka taea te tuku mahara ma te mahi PHP mysqli_free_result().

Ko te tauira e whai ake nei e whakaatu ana i te whakamahinga o tenei mahi.

Akoranga

Whakamātauria ngā tauira e whai ake nei:

Pumahara koreutu me 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);
?>