how use order by clause in group by statement - php

Question

I have two table tbl_issue_log, tbl_magazine_issue
tbl_issue_log
============
+----------+--------+--------+-----------+---------------------+
| issue_id | mag_id | log_id | operation | updated_time |
+----------+--------+--------+-----------+---------------------+
| 2 | 1 | 1 | 1 | 2014-01-30 21:29:44 |
| 3 | 4 | 1 | 1 | 2015-01-30 21:29:44 |
| 2 | 1 | 1 | 3 | 2015-01-31 21:29:44 |
+----------+--------+--------+-----------+---------------------+
tbl_magazine_issue
=================
+----------+-------------+-------------+------------------+------------+------------+-------------------+---------------+
| ISSUE_ID | ISSUE_NAME | MAGAZINE_ID | COVER_PAGE_THUMB | FROM_DATE | TO_DATE | issue_description | login_page_no |
+----------+-------------+-------------+------------------+------------+------------+-------------------+---------------+
| 2 | test issue | 1 | cover page | 2014-01-30 | 2015-01-30 | sdssdg fsdf | 20 |
| 3 | test issue1 | 4 | cover page1 | 2014-01-30 | 2015-01-30 | sdssdg fsdf | 20 |
+----------+-------------+-------------+------------------+------------+------------+-------------------+---------------+
in tbl_issue_log contain multiple records for same issue id. i want only one issue at a time
and this must latest updated time.
My query is this
SELECT
`tbl_issue_log`.`operation`,
`tbl_magazine_issue`.`ISSUE_ID`,
`tbl_magazine_issue`.`ISSUE_NAME`,
`tbl_magazine_issue`.`MAGAZINE_ID`,
`tbl_magazine_issue`.`COVER_PAGE_THUMB`,
`tbl_magazine_issue`.`FROM_DATE`,
`tbl_magazine_issue`.`TO_DATE`,
`tbl_magazine_issue`.`issue_description`,
`tbl_magazine_issue`.`login_page_no`
FROM
`tbl_issue_log`
LEFT JOIN
`tbl_magazine_issue` ON tbl_magazine_issue.ISSUE_ID = tbl_issue_log.issue_id
WHERE
(tbl_issue_log.mag_id = '1')
AND (tbl_magazine_issue.ISSUE_STATUS = 3)
AND (tbl_issue_log.updated_time > '2014-02-25 00:42:22')
GROUP BY tbl_issue_log.issue_id
ORDER BY tbl_issue_log updated_time DESC;
Here i got issue id based output . But not getting the latest updated timeed record.
If any one about this please help me.

Answer 1

Try this
SELECT * FROM
(SELECT
`tbl_issue_log`.`operation`,
`tbl_magazine_issue`.`ISSUE_ID`,
`tbl_magazine_issue`.`ISSUE_NAME`,
`tbl_magazine_issue`.`MAGAZINE_ID`,
`tbl_magazine_issue`.`COVER_PAGE_THUMB`,
`tbl_magazine_issue`.`FROM_DATE`,
`tbl_magazine_issue`.`TO_DATE`,
`tbl_magazine_issue`.`issue_description`,
`tbl_magazine_issue`.`login_page_no`
FROM
`tbl_issue_log`
LEFT JOIN
`tbl_magazine_issue` ON tbl_magazine_issue.ISSUE_ID = tbl_issue_log.issue_id
WHERE
(tbl_issue_log.mag_id = '1')
AND (tbl_magazine_issue.ISSUE_STATUS = 3)
AND (tbl_issue_log.updated_time > '2014-02-25 00:42:22')
ORDER BY tbl_issue_log.updated_time DESC ) TEMP_TABLE
GROUP BY ISSUE_ID

Answer 2

Can you try changing order by clause as
ORDER BY tbl_issue_log.updated_time DESC;
Edit ---
As you are grouping on issue_id, mysql will select first row that matches the issue_id. The order by runs later which essentially does not return what you are looking for. You may need to use a subquery approach for this.
select some_table.* FROM
(
SELECT
MAX(tbl_issue_log.updated_time) AS updated_time,
`tbl_issue_log`.`operation`,
`tbl_magazine_issue`.`ISSUE_ID`,
`tbl_magazine_issue`.`ISSUE_NAME`,
`tbl_magazine_issue`.`MAGAZINE_ID`,
`tbl_magazine_issue`.`COVER_PAGE_THUMB`,
`tbl_magazine_issue`.`FROM_DATE`,
`tbl_magazine_issue`.`TO_DATE`,
`tbl_magazine_issue`.`issue_description`,
`tbl_magazine_issue`.`login_page_no`
FROM
`tbl_issue_log`
LEFT JOIN
`tbl_magazine_issue` ON tbl_magazine_issue.ISSUE_ID = tbl_issue_log.issue_id
WHERE
(tbl_issue_log.mag_id = '1')
AND (tbl_magazine_issue.ISSUE_STATUS = 3)
AND (tbl_issue_log.updated_time > '2014-02-25 00:42:22')
GROUP BY tbl_issue_log.issue_id
) some_table
ORDER BY some_table.updated_time DESC;