How to write a PHP script in which I join two MySQL tables using MySQL JOINS?-PHP Tutorial-php.cn

How to write a PHP script in which I join two MySQL tables using MySQL JOINS?

王林

Release： 2023-08-20 11:58:02

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如何编写PHP脚本，使用MySQL JOINS在其中连接两个MySQL表格？

We can use the MySQL JOIN syntax to connect the two tables to the PHP function mysql_query(). This function is used to execute a SQL command, and then another PHP function mysql_fetch_array() can be used to fetch all selected data.

To illustrate this, we have the following example −

Example

In this example we have used two MySQL tables with the following data−

mysql> SELECT * FROM tcount_tbl;
+-----------------+----------------+
| tutorial_author | tutorial_count |
+-----------------+----------------+
| mahran          |      20        |
| mahnaz          |      NULL      |
| Jen             |      NULL      |
| Gill            |      20        |
| John Poul       |       1        |
| Sanjay          |       1        |
+-----------------+----------------+
6 rows in set (0.01 sec)

mysql> SELECT * from tutorials_tbl;
+-------------+----------------+-----------------+-----------------+
| tutorial_id | tutorial_title | tutorial_author | submission_date |
+-------------+----------------+-----------------+-----------------+
|      1      |   Learn PHP    |   John Poul     |   2007-05-24    |
|      2      | Learn MySQL    |   Abdul S       |   2007-05-24    |
|      3      | JAVA Tutorial  |   Sanjay        |   2007-05-06    |
+-------------+----------------+-----------------+-----------------+
3 rows in set (0.00 sec)

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Now, below is a PHP script that will join the table to select all the authors from table tutorials_tbl and will select the corresponding number of tutorials from tcount_tbl.

<?php
   $dbhost = &#39;localhost:3036&#39;;
   $dbuser = &#39;root&#39;;
   $dbpass = &#39;rootpassword&#39;;
   $conn = mysql_connect($dbhost, $dbuser, $dbpass);

   if(! $conn ) {
      die(&#39;Could not connect: &#39; . mysql_error());
   }

   $sql = &#39;SELECT a.tutorial_id, a.tutorial_author, b.tutorial_count
   FROM tutorials_tbl a, tcount_tbl b
   WHERE a.tutorial_author = b.tutorial_author&#39;;

   mysql_select_db(&#39;TUTORIALS&#39;);
   $retval = mysql_query( $sql, $conn );

   if(! $retval ) {
      die(&#39;Could not get data: &#39; . mysql_error());
   }

   while($row = mysql_fetch_array($retval, MYSQL_ASSOC)) {
      echo "Author:{$row[&#39;tutorial_author&#39;]} <br> ".
         "Count: {$row[&#39;tutorial_count&#39;]} <br> ".
         "Tutorial ID: {$row[&#39;tutorial_id&#39;]} <br> ".
         "--------------------------------<br>";
   }
   echo "Fetched data successfully</p><p>";
   mysql_close($conn);
?>

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