Faʻafefea ona faʻaoga MySQL i fea faʻamatalaga? lea o lo'o iai le fuaiupu e tele fa'asologa o tulaga

MySQL databaseFa'afefea ona fa'aoga le fa'amatalaga o fea? lea o lo'o iai le fuaiupu e tele fa'asologa o tulaga

MySQL WHERE fuaiupu

Matou te iloa e faʻaaoga le SQL SELECT faʻamatalaga e faitau ai faʻamatalaga mai le laulau MySQL.

Ina ia filifilia faʻamaumauga mai se laulau, faʻaopoopo se fuaiupu WHERE ile faʻamatalaga SELECT.

kalama

O loʻo taua i lalo le faʻasologa lautele o se faʻamatalaga SQL SELECT e faitau faʻamatalaga mai se laulau faʻamaumauga e faʻaaoga ai le WHERE fuaiupu:

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

• E mafai ona e fa'aogaina se tasi pe sili atu laulau i le fa'amatalaga o fesili, fa'aoga koma i le va o laulau, Vaevae, ma fa'aoga le fa'amatalaga WHERE e fa'atulaga ai tulaga fa'atatau.
• E mafai ona e faʻamaonia soʻo se tulaga i le WHERE fuaiupu.
• E mafai ona e fa'ama'oti se tasi pe sili atu tu'utu'uga e fa'aaoga ai le MA po'o le OR.
• Ole fuaiupu WHERE e mafai foi ona faʻaogaina ile SQL's DELETE poʻo le UPDATE poloaiga.
• O le fuaiupu WHERE e tutusa ma le tulaga i le gagana polokalame, faitau faʻamatalaga faʻamaonia e tusa ai ma le tau o le fanua i le laulau MySQL.

Ole lisi o lo'o mulimuli mai e mafai ona fa'aogaina ile WHERE fuaiupu.

O faʻataʻitaʻiga i le laulau o loʻo i lalo e faʻapea o le A e 10 ma le B e 20

Ole fuaiupu WHERE e aoga tele pe a tatou mananao e faitau faʻamatalaga faʻamaonia mai le laulau faʻamaumauga MySQL.

O le fa'aogaina o le ki autu e fai ma fesili fa'apitoa i le WHERE fuaiupu e matua vave lava.

Afai e leai ni fa'amaumauga tutusa i le laulau, e leai se fa'amatalaga e toe fa'afo'i mai e le fesili.

faitau faʻamatalaga mai le faʻatonuga vave

Matou te faʻaogaina le WHERE fuaiupu i le SQL SELECT faʻamatalaga e faitau ai faʻamatalaga i le MySQL data table chenweiliang_tbl:

Fa'ata'ita'iga

O le fa'ata'ita'iga o lo'o mulimuli mai o le a faitau uma fa'amaumauga i le laulau chenweiliang_tbl lea o le tau o le fanua chenweiliang_author o Sanjay:

Fa'atusatusaga fa'atusa ile MySQL's WHERE fuaiupu e fa'aletonu mata'upu.E mafai ona e fa'aogaina le upu BINARY e fa'amaonia ai le fa'atusatusaga o manoa i le WHERE fuaiupu e fa'atatau i mata'itusi.

O le fa'ata'ita'iga lea:

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)

faaaogaina i le faataitaiga PINARI keyword, e mata'itusi, o lea chenweiliang_author='chenweiliang.com' Ole tulaga ole fesili ole fa'amaumauga.

Faitau faʻamatalaga e faʻaaoga ai le PHP script

E mafai ona e fa'aogaina le galuega PHP mysqli_query() ma le fa'atonuga tutusa a le SQL SELECT ma se fuaiupu WHERE e maua ai fa'amaumauga.

O lenei galuega e faʻaaogaina e faʻatino ai faʻatonuga SQL ona faʻapipiʻi uma ai lea o faʻamaumauga e ala i le PHP galuega mysqli_fetch_array().

Fa'ata'ita'iga

Ole fa'ata'ita'iga lea ole a toe fo'i mai ile laulau chenweiliang_tbl e fa'aaoga ai le tau ole fanua chenweiliang_author pei chenweiliang.com faamaumauga o:

MySQL WHERE fuaiupu suʻega:

<?
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);
?>