Question

i am facing a strange issue, if i am checking the mysql query with PHP then i didn’t get the exact result according to mysql query.

But the same query if i run then i get the expected result, here is mysql query:

SELECT id, follow_up_datetime, followed_by, follow_up_status, case_time_zone, description, case_id
FROM case_note
WHERE TYPE LIKE '%follow-up-open%'
AND (
    follow_up_datetime LIKE '%2013-01-08%'
    OR date( follow_up_datetime ) < '2013-01-08'
)
AND follow_up_status <= '1'
GROUP BY case_id
ORDER BY case_id DESC
LIMIT 0 , 30

the result of this query is :

but when i use the same query with php then i get the the wrong ids:
PHP

//current date is "2013-01-08";
$follow_q = "SELECT id, follow_up_datetime, followed_by, follow_up_status, case_time_zone, description, case_id
                 FROM case_note
                 WHERE `type` LIKE '%follow-up-open%'
                 AND (
                 follow_up_datetime LIKE '%$current_date%'
                 OR date(follow_up_datetime) < '$current_date'
                 )
                 AND follow_up_status <= '1' 
                 GROUP BY case_id 
                 ORDER BY case_id DESC";
$follow_r = mysql_query($follow_q) or die('Error in Query!<br />' . mysql_error());

this query providing me the id’s like 53, 84, 47, 36.

last three id’s are correct but the first is not correct. i want first id is 139. Can anyone please help to find out the exact problem?

UPDATE: here i have update the result of id 53

Answer 1

A few tips concerning your query itself:

Your follow_up_datetime should be a type timestamp or datetime

You don’t need the LIKE operator in your date condition.

DATE( `follow_up_datetime` ) = '2013-01-08' 
OR 
DATE( `follow_up_datetime` ) < '2013-01-08' 

This can be shortened into

DATE( `follow_up_datetime` ) <= '2013-01-08' 

If you always compare to the current date, you can use CURRENT_DATE

DATE( `follow_up_datetime` ) <= CURRENT_DATE

Don’t compare a col of type int to a string which will force MySQL to cast all values of the col follow_up_status to string.

`follow_up_status` <= 1

Are you sure you need LIKE for the type condition?

`type` = 'follow_up_open'

Would be much faster.

PHP documentation about the MySQL extension:

This extension is deprecated as of PHP 5.5.0, and will be removed in the future. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information.

---

EDIT:

Just realized you GROUP BY case_id.
If both, id 53 and id 139 have the same case_id MySQL needs to know which row can be discarded. If you don’t give this information, one of the two rows is discarded more or less randomly.

To work around this problem use a aggregate function. in your case MIN() would deliver the desired result.

The whole query cleaned up using PHP heredoc notation:

$follow_q = <<< EOQ
    SELECT 
        MIN( `id` ) AS `id`,
        `follow_up_datetime`,
        `followed_by`,
        `follow_up_status`,
        `case_time_zone`,
        `description`,
        `case_id`
    FROM
        `case_note`
    WHERE
        `type` = 'follow-up-open'
         AND
        `follow_up_datetime` <= '{$current_date}'
        AND
        `follow_up_status <= 1
    GROUP BY 
        `case_id`
    ORDER BY 
        `case_id` DESC
EOQ;