Bawo ni lati beere MySQL bi? Lilo iru alaye ni aaye data MySQL

MySQL Bawo ni lati beere bi?mysql databaseKannada fẹran lilo alaye

MySQL LIKE gbolohun ọrọ

A mọ lati lo aṣẹ SQL SELECT lati ka data ni MySQL, ati pe a le lo gbolohun WHERE ninu alaye YAN lati gba awọn igbasilẹ pato.

Ami dogba le ṣee lo ni gbolohun NIBI = Lati ṣeto awọn ipo fun gbigba data, gẹgẹbi "chenweiliang_author = 'chenweiliang.com'".

Ṣugbọn nigbami a nilo lati gba gbogbo awọn igbasilẹ ti aaye chenweiliang_author ni awọn ohun kikọ "COM" ninu, lẹhinna a nilo lati lo gbolohun ọrọ SQL LIKE ni gbolohun WHERE.

Lilo awọn ami ogorun ninu SQL JORA awọn gbolohun ọrọ %ohun kikọ lati ṣe aṣoju eyikeyi ohun kikọ, iru si aami akiyesi ni UNIX tabi awọn ikosile deede *,

Ti a ko ba lo ami ogorun %, BI gbolohun ọrọ pẹlu ami dogba = Ipa naa jẹ kanna.

girama

Atẹle ni sintasi gbogbogbo ti alaye SQL SELECT lati ka data lati inu tabili data kan nipa lilo gbolohun JORA:

SELECT field1, field2,...fieldN 
FROM table_name
WHERE field1 LIKE condition1 [AND [OR]] filed2 = 'somevalue'

• O le pato ipo eyikeyi ninu gbolohun ọrọ NIBI.
• O le lo gbolohun LIKE ni gbolohun ọrọ NIBI.
• O le lo gbolohun LIKE ni aaye ti ami dọgba =,
• LIKE ni a maa n ni nkan ṣe pẹlu % Ti a lo papọ, ti o jọra si wiwa ohun kikọ meta.
• O le lo ATI tabi TABI lati pato ọkan tabi diẹ ẹ sii awọn ipo.
• O le lo NIBI...FẸRẸ gbolohun ọrọ ni Parẹ tabi awọn pipaṣẹ imudojuiwọn lati tokasi awọn ipo.

Lilo gbolohun LIKE ni aṣẹ aṣẹ

Ni isalẹ a yoo lo WHERE...FẸRẸ gbolohun ọrọ ninu aṣẹ SQL SELECT lati ka data lati inu tabili data MySQL chenweiliang_tbl.

Apeere

Atẹle ni bii a yoo ṣe gba aaye chenweiliang_author ninu tabili chenweiliang_tbl pẹlu isọwọsare fun gbogbo awọn igbasilẹ ti o pari pẹlu:

mysql> use chenweiliang;
Database changed
mysql> SELECT * from chenweiliang_tbl WHERE chenweiliang_author LIKE '%COM';
+-----------+---------------+---------------+-----------------+
| 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 |
+-----------+---------------+---------------+-----------------+
2 rows in set (0.01 sec)

Lilo LIKE gbolohun ọrọ ni PHP akosile

O le lo iṣẹ PHP mysqli_query() ati aṣẹ SQL SELECT kanna pẹlu IBI kan...FẸRẸ gbolohun ọrọ lati gba data.

Iṣẹ yii ni a lo lati ṣiṣẹ awọn aṣẹ SQL ati lẹhinna jade data fun gbogbo awọn ibeere nipasẹ iṣẹ PHP mysqli_fetch_assoc().

Ṣugbọn ti o ba jẹ alaye SQL kan ni lilo WHERE... BI gbolohun ọrọ ni DELETE tabi imudojuiwọn, ko si iwulo lati lo iṣẹ mysqli_fetch_array ().

Apeere

Eyi ni bii a ṣe lo iwe afọwọkọ PHP kan lati ka gbogbo awọn igbasilẹ ti o pari ni COM ni aaye chenweiliang_author ninu tabili 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
 WHERE chenweiliang_author LIKE "%COM"';
 
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);
?>