加入两个表问题

Question

I have two Tables:

Table-1: notes


Table-2: contacts

My basic objective is to perform following query:

I have written following code to do this:

<?php
require_once('config.php');

$nwhere = "WHERE note_text LIKE '%".addslashes($_GET['s'])."%' ";
$cwhere = "contact_text LIKE '%".addslashes($_GET['s'])."%' ";
$result = mysql_query("SELECT * FROM contacts INNER JOIN notes ON contact_id = note_contact $nwhere OR $cwhere ORDER BY contact_id");

while($row = mysql_fetch_array($result))
{
echo $row['contact_id'];
echo '<br/>';
}
?>

When Search Text is azeem , the above code prints only 4001 , however output should be:
4000
4001

Also I dont want to repeat contact_id in Output.
Please suggest.

Code After correction by :

$where_clause = " where contacts.contact_text like '%".addslashes($_GET['s'])."%' or    notes.note_text like '%".addslashes($_GET['s'])."%'";
$result = mysql_query("select notes.note_id, notes.note_contact, contacts.contact_id,  contacts.contact_text, notes.note_text from contacts left outer join notes on contacts.contact_id=notes.note_contact $where_clause");
while($row = mysql_fetch_array($result))
{
echo $row['contact_id'];
echo '<br/>';
}
?>

This code picks up correct rows from tables but there is one minor issue that it repeats the output (contact_id). For example it showed following output when i gave search parameter nawaz :
4001
4001
4001
4001
4001
4002
4003

Thanks for your help, please help me out to fix this.

Answer 1

If you don't want a column repeated, you can't use SELECT * FROM but rather you will need to use the column names you want to select.

You aren't getting the 4000 result you are expecting because you are doing an inner join on a field that doesn't exist in the other table. (Azeem = 4000, but no note_contact exists for user 4000).

You should consider switching to an outer join instead. Maybe something like this:

select
    a.note_id,
    a.note_contact,
    b.contact_text,
    b.note_text
from
    contacts a
        left outer join notes b
            on a.contact_id=b.note_contact
where
    a.contact_text like '%azeem%'
    or b.note_text like '%azeem%'

Edit: Seems we were both still working - I gave made a sqlFiddle which has the basic schema and a working outer join for the example.

My create schema is:

mysql> CREATE TABLE `contacts` (
    ->   `contact_id` int(4) DEFAULT NULL,
    ->   `contact_text` varchar(40) DEFAULT NULL,
    ->   `contact_email` varchar(40) DEFAULT NULL
    -> ) ENGINE=InnoDB DEFAULT CHARSET=latin1;
Query OK, 0 rows affected (0.00 sec)

mysql> 
mysql> CREATE TABLE `notes` (
    ->   `note_id` int(3) NOT NULL AUTO_INCREMENT,
    ->   `note_contact` int(4) DEFAULT NULL,
    ->   `note_text` tinytext,
    ->   PRIMARY KEY (`note_id`)
    -> ) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=7 ;
Query OK, 0 rows affected (0.00 sec)

mysql> 
mysql> INSERT INTO `contacts` (`contact_id`, `contact_text`, `contact_email`) VALUES
    -> (4000, 'azeem', 'azeem@big.com'),
    -> (4001, 'nawaz', 'azeem@big.com'),
    -> (4002, 'nawaz', 'azeem@big.com');
Query OK, 3 rows affected (0.00 sec)
Records: 3  Duplicates: 0  Warnings: 0

mysql> 
mysql> INSERT INTO `notes` (`note_id`, `note_contact`, `note_text`) VALUES
    -> (1, 4001, 'I am text1'),
    -> (2, 4001, 'I am text2'),
    -> (3, 4001, 'my name is azeem'),
    -> (4, 4001, 'come here'),
    -> (5, 4001, 'I don''t want to'),
    -> (6, 4003, 'My text is clear.');
Query OK, 6 rows affected (0.01 sec)
Records: 6  Duplicates: 0  Warnings: 0

outer Join Query:

mysql> select
    -> b.note_id,
    -> b.note_contact,
    -> a.contact_text,
    -> b.note_text
    -> from
    -> contacts a
    -> left outer join notes b
    -> on a.contact_id=b.note_contact
    -> where
    -> a.contact_text like '%azeem%'
    -> or b.note_text like '%azeem%';
+---------+--------------+--------------+------------------+
| note_id | note_contact | contact_text | note_text        |
+---------+--------------+--------------+------------------+
|    NULL |         NULL | azeem        | NULL             |
|       3 |         4001 | nawaz        | my name is azeem |
+---------+--------------+--------------+------------------+
2 rows in set (0.00 sec)

Code working from Nida:

$where_clause = " where contacts.contact_text like '%".addslashes($_GET['s'])."%' or notes.note_text like '%".addslashes($_GET['s'])."%'";
$result = mysql_query("select distinct contacts.contact_id from contacts left outer join notes on contacts.contact_id=notes.note_contact $where_clause")