Maitiro ekushandisa MySQL kupi chirevo? uko clause multiple conditions syntax

MySQL databaseNzira yekushandisa sei chirevo? uko clause multiple conditional syntax

MySQL KUPI clause

Isu tinoziva kushandisa SQL SELECT statement kuverenga data kubva kuMySQL tafura.

Kuti usarudze data kubva patafura, wedzera a WHERE clause kune SELECT statement.

girama

Inotevera ndiyo yakajairika syntax yeSQL SELECT statement yekuverenga data kubva patafura yedata uchishandisa iyo WHERE clause:

SELECT field1, field2,...fieldN FROM table_name1, table_name2...
[WHERE condition1 [AND [OR]] condition2.....

• Unogona kushandisa tafura imwe kana kupfuura muchirevo chemubvunzo, uchishandisa koma pakati pematafura, Kupatsanura, uye shandisa iyo WHERE chirevo kuseta mamiriro emubvunzo.
• Iwe unogona kutsanangura chero mamiriro muWHERE clause.
• Unogona kutsanangura imwe kana mamwe mamiriro uchishandisa AND kana OR.
• Iyo WHERE clause inogona zvakare kushandiswa neSQL's DELETE kana UPDATE mirairo.
• The WHERE clause yakafanana neiyo kana mamiriro mumitauro yemaitiro, uye inoverenga iyo yakatarwa data maererano nehuwandu hwemunda muMySQL tafura.

Inotevera rondedzero yevashandisi vanogona kushandiswa muchikamu cheWHERE.

Mienzaniso iri patafura iri pazasi inofungidzira kuti A igumi uye B imakumi maviri

The WHERE clause inobatsira zvikuru kana tichida kuverenga iyo yakatarwa data kubva kuMySQL data tafura.

Kushandisa kiyi yekutanga semubvunzo une chirevo muWHERE clause inokurumidza.

Kana iyo nzira yakapihwa isina marekodhi anoenderana mutafura, mubvunzo haudzose data.

verenga data kubva kune command prompt

Tichashandisa WHERE clause muSQL SELECT statement kuverenga data iri muMySQL data table chenweiliang_tbl:

muenzaniso

Muenzaniso unotevera uchaverenga marekodhi ese ari patafura chenweiliang_tbl uko kukosha kwechikamu chenweiliang_author kuri Sanjay:

Kuenzanisa kwetambo muMySQL's WHERE clause haina-kunzwa.Iwe unogona kushandisa BINARY kiyi kiyi kutsanangura kuti tambo kuenzanisa muWHERE clause inobata nyaya.

Muenzaniso unotevera:

mysql> SELECT * from chenweiliang_tbl WHERE BINARY chenweiliang_author='chenweiliang.com';
Empty set (0.01 sec)
 
mysql> SELECT * from chenweiliang_tbl WHERE BINARY chenweiliang_author='chenweiliang.com';
+-----------+---------------+---------------+-----------------+
| chenweiliang_id | chenweiliang_title | chenweiliang_author | submission_date |
+-----------+---------------+---------------+-----------------+
| 3 | JAVA 教程 | chenweiliang.com | 2016-05-06 |
| 4 | 学习 Python | chenweiliang.com | 2016-03-06 |
+-----------+---------------+---------------+-----------------+
2 rows in set (0.01 sec)

inoshandiswa mumuenzaniso BINARI keyword, inyaya-inonzwa, saka chenweiliang_author='chenweiliang.com' Mamiriro emubvunzo haana data.

Verenga data uchishandisa PHP script

Unogona kushandisa PHP basa mysqli_query() uye yakafanana SQL SELECT command ine WHERE clause kuti uwane iyo data.

Iri basa rinoshandiswa kuita SQL mirairo uye wozoburitsa ese akabvunzwa data kuburikidza neiyo PHP basa mysqli_fetch_array().

muenzaniso

Muenzaniso unotevera uchadzoka kubva patafura ye chenweiliang_tbl uchishandisa chenweiliang_author field value se chenweiliang.com rekodhi ye:

MySQL WHERE clause test:

<?
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");
 
// 读取 chenweiliang_author 为 chenweiliang.com 的数据
$sql = 'SELECT chenweiliang_id, chenweiliang_title, 
 chenweiliang_author, submission_date
 FROM chenweiliang_tbl
 WHERE chenweiliang_author="chenweiliang.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 MySQL WHERE 子句测试<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>';
// 释放内存
mysqli_free_result($retval);
mysqli_close($conn);
?>