MYSQL TUTORIALS - MySQL Using Join
MySQL Using Join
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Example:
root@host# mysql -u root -p password; Enter password:******* mysql> use TUTORIALS; Database changed 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) mysql>ADVERTISEMENTS
mysql> SELECT a.tutorial_id, a.tutorial_author, b.tutorial_count -> FROM tutorials_tbl a, tcount_tbl b -> WHERE a.tutorial_author = b.tutorial_author; +-------------+-----------------+----------------+ | tutorial_id | tutorial_author | tutorial_count | +-------------+-----------------+----------------+ | 1 | John Poul | 1 | | 3 | Sanjay | 1 | +-------------+-----------------+----------------+ 2 rows in set (0.01 sec) mysql>ADVERTISEMENTSExample:
<?php $dbhost = 'localhost:3036'; $dbuser = 'root'; $dbpass = 'rootpassword'; $conn = mysql_connect($dbhost, $dbuser, $dbpass); if(! $conn ) { die('Could not connect: ' . mysql_error()); } $sql = 'SELECT a.tutorial_id, a.tutorial_author, b.tutorial_count FROM tutorials_tbl a, tcount_tbl b WHERE a.tutorial_author = b.tutorial_author'; mysql_select_db('TUTORIALS'); $retval = mysql_query( $sql, $conn ); if(! $retval ) { die('Could not get data: ' . mysql_error()); } while($row = mysql_fetch_array($retval, MYSQL_ASSOC)) { echo "Author:{$row['tutorial_author']} <br> ". "Count: {$row['tutorial_count']} <br> ". "Tutorial ID: {$row['tutorial_id']} <br> ". "--------------------------------<br>"; } echo "Fetched data successfully\n"; mysql_close($conn); ?>Example:
root@host# mysql -u root -p password; Enter password:******* mysql> use TUTORIALS; Database changed mysql> SELECT a.tutorial_id, a.tutorial_author, b.tutorial_count -> FROM tutorials_tbl a LEFT JOIN tcount_tbl b -> ON a.tutorial_author = b.tutorial_author; +-------------+-----------------+----------------+ | tutorial_id | tutorial_author | tutorial_count | +-------------+-----------------+----------------+ | 1 | John Poul | 1 | | 2 | Abdul S | NULL | | 3 | Sanjay | 1 | +-------------+-----------------+----------------+ 3 rows in set (0.02 sec)