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I tried a lot, but I cannot figure out a way to do this:
I have a table with (not unique) IDs and dates. All entries should be selected in the end, but they need to be sorted.
Table:
+----+------------+
| id | date |
+----+------------+
| 1 | 2017-12-10 |
| 1 | 2015-05-22 |
| 7 | 2016-04-05 |
| 2 | 2017-12-12 |
| 2 | 2014-03-10 |
| 7 | 2016-01-14 |
| 1 | 2016-08-17 |
+----+------------+
What I need:
+----+------------+
| id | date |
+----+------------+
| 2 | 2017-12-12 |
| 2 | 2014-03-10 |
| 1 | 2017-12-10 |
| 1 | 2016-08-17 |
| 1 | 2015-05-22 |
| 7 | 2016-04-05 |
| 7 | 2016-01-14 |
+----+------------+
I need everything "grouped" by the ids, starting with the id that has the most recent date linked to it.
id: 2 / date: 2017-12-12
has the most recent date, so now all rows with Id 2 follow, ordered by the date descending. After that, which "block" of ids comes next is determined again by the next most recent date and so on.
Using a subquery that groups by id, we get the max date, then joining this to the source data gives us the max date on every row to sort by.
SQL Fiddle
MySQL 5.6 Schema Setup:
CREATE TABLE Table1
(`id` int, `date` datetime)
;
INSERT INTO Table1
(`id`, `date`)
VALUES
(1, '2017-12-10 00:00:00'),
(1, '2015-05-22 00:00:00'),
(7, '2016-04-05 00:00:00'),
(2, '2017-12-12 00:00:00'),
(2, '2014-03-10 00:00:00'),
(7, '2016-01-14 00:00:00'),
(1, '2016-08-17 00:00:00')
;
Query 1:
select t.*
from table1 t
inner join (
select id, max(`date`) maxdate
from table1
group by id
) g on t.id = g.id
order by g.maxdate DESC, t.id, t.date DESC
Results:
| id | date |
|----|----------------------|
| 2 | 2017-12-12T00:00:00Z |
| 2 | 2014-03-10T00:00:00Z |
| 1 | 2017-12-10T00:00:00Z |
| 1 | 2016-08-17T00:00:00Z |
| 1 | 2015-05-22T00:00:00Z |
| 7 | 2016-04-05T00:00:00Z |
| 7 | 2016-01-14T00:00:00Z |
if your table is stack
SELECT * FROM `stack` LEFT OUTER JOIN (SELECT * FROM `stack` GROUP BY `id` )t1 ON
`stack`.`id` = t1.`id` ORDER BY t1.`date` DESC,`stack`.`date` DESC
I want my tables to output something like this
---------------------------------------------------------------------------------------------
| date | location | time | delegate 1 | delegate 2 |
|--------------------------------------------------------------------------------------------
| 2015-12-07 | Table 1 | 9:00 | first_name_4 last_name_4 | first_name_5 last_name_5 |
|--------------------------------------------------------------------------------------------
| | 9:30 | first_name_4 last_name_4 | first_name_6 last_name_6 |
|--------------------------------------------------------------------------------------------
| | 9:30 | first_name_3 last_name_3 | first_name_7 last_name_7 |
|--------------------------------------------------------------------------------------------
| | 9:00 | first_name_3 last_name_3 | first_name_7 last_name_7 |
|--------------------------------------------------------------------------------------------
Here are the tables on my db
meetings table
-------------------------------------------------------------------------------------------------
| id | date_id | time_id | location_id | delegate_id_1 | delegate_id_2 | status |
|------------------------------------------------------------------------------------------------
| 1 | 1 | 1 | 1 | 4 | 5 | A |
|------------------------------------------------------------------------------------------------
| 2 | 1 | 2 | 1 | 4 | 6 | A |
|------------------------------------------------------------------------------------------------
| 3 | 1 | 1 | 1 | 2 | 6 | P |
|------------------------------------------------------------------------------------------------
| 4 | 1 | 2 | 1 | 1 | 3 | A |
|------------------------------------------------------------------------------------------------
| 5 | 1 | 1 | 1 | 1 | 3 | A |
|------------------------------------------------------------------------------------------------
users table
-----------------------------------------
| id | first_name | last_name |
|----------------------------------------
| 1 | first_name_1 | last_name_1 |
|----------------------------------------
| 2 | first_name_2 | last_name_2 |
|----------------------------------------
| 3 | first_name_3 | last_name_3 |
|----------------------------------------
| 4 | first_name_4 | last_name_4 |
|----------------------------------------
| 5 | first_name_5 | last_name_5 |
|----------------------------------------
| 6 | first_name_6 | last_name_6 |
|----------------------------------------
locations table
-----------------------------
| id | location_name |
|----------------------------
| 1 | Table 1 |
|----------------------------
time table
-------------------------
| id | meeting_time |
|------------------------
| 1 | 9:00:00 |
|------------------------
| 1 | 9:30:00 |
|------------------------
dates table
-------------------------
| id | meeting_date |
|------------------------
| 1 | 2015-12-07 |
|------------------------
| 2 | 2015-12-08 |
|------------------------
| 3 | 2015-12-09 |
|------------------------
My initial query goes like this
-- $query_date
SELECT meeting_date
FROM dates
WHERE meeting_date = '2015-12-07'
-- $query_location
SELECT location_name.location
from location
LEFT JOIN meetings
ON meetings.location_id=location.id
LEFT JOIN date
ON meetings.date_id=date.id
WHERE meeting_date.dates = '2015-12-07'
Now, here's the part where I got it wrong.
-- $query_final
SELECT meeting_time.time, delegate1.first_name AS first_name_1,
delegate1.last_name AS last_name_1, delegate2.first_name AS first_name_2,
delegate2.last_name AS last_name_2
FROM meetings
INNER JOIN users delegate1
ON meetings.delegate_id_1=users.id
LEFT JOIN users delegate2
ON meetings.delegate_id_2=users.id
WHERE meetings.status='A'
The results on my last query give me unexpected results since the results show more entries than my meetings table.
I know the queries I made are costly but I don't know how to make a more optimized query. I don't even know if it's possible to get the results into a single query only. Any help well do. Thanks.
You can bring back everything with a single query with the right JOIN.
Be Careful, when you use column name on SQL, the syntax is TABLE.COLUMN_NAME, it seem you mistake on the order quit often...
I changed some table name as you sometime use an s at the end and sometime no.
As time and date are SQL keyword, it's better with s everywhere
SQL Fiddle
MySQL 5.6 Schema Setup:
CREATE TABLE meetings (`id` int, `date_id` int, `time_id` int, `location_id` int, `delegate_id_1` int, `delegate_id_2` int, `status` varchar(1));
INSERT INTO meetings (`id`, `date_id`, `time_id`, `location_id`, `delegate_id_1`, `delegate_id_2`, `status`)
VALUES (1, 1, 1, 1, 4, 5, 'A'),
(2, 1, 2, 1, 4, 6, 'A'),
(3, 1, 1, 1, 2, 6, 'P'),
(4, 1, 2, 1, 1, 3, 'A'),
(5, 1, 1, 1, 1, 3, 'A');
CREATE TABLE users (`id` int, `first_name` varchar(12), `last_name` varchar(11));
INSERT INTO users (`id`, `first_name`, `last_name`)
VALUES (1, 'first_name_1', 'last_name_1'),
(2, 'first_name_2', 'last_name_2'),
(3, 'first_name_3', 'last_name_3'),
(4, 'first_name_4', 'last_name_4'),
(5, 'first_name_5', 'last_name_5'),
(6, 'first_name_6', 'last_name_6');
CREATE TABLE locations (`id` int, `location_name` varchar(7));
INSERT INTO locations (`id`, `location_name`)
VALUES (1, 'Table 1');
CREATE TABLE times (`id` int, `meeting_time` varchar(7));
INSERT INTO times (`id`, `meeting_time`)
VALUES (1, '9:00:00'),
(2, '9:30:00') ;
CREATE TABLE dates (`id` int, `meeting_date` varchar(10)) ;
INSERT INTO dates (`id`, `meeting_date`)
VALUES (1, '2015-12-07'),
(2, '2015-12-08'),
(3, '2015-12-09') ;
Query 1:
-- $query_final
SELECT locations.location_name,
`times`.meeting_time,
delegate1.first_name AS first_name_1,
delegate1.last_name AS last_name_1,
delegate2.first_name AS first_name_2,
delegate2.last_name AS last_name_2
FROM meetings
LEFT JOIN locations
ON meetings.location_id=locations.id
LEFT JOIN dates
ON meetings.date_id=`dates`.id
LEFT JOIN times
ON meetings.time_id=`times`.id
INNER JOIN users delegate1
ON meetings.delegate_id_1 = delegate1.id
LEFT JOIN users delegate2
ON meetings.delegate_id_2 = delegate2.id
WHERE
meetings.status = 'A'
AND dates.meeting_date = '2015-12-07'
Results:
| location_name | meeting_time | first_name | last_name | first_name | last_name |
|---------------|--------------|--------------|-------------|--------------|-------------|
| Table 1 | 9:00:00 | first_name_1 | last_name_1 | first_name_3 | last_name_3 |
| Table 1 | 9:30:00 | first_name_1 | last_name_1 | first_name_3 | last_name_3 |
| Table 1 | 9:00:00 | first_name_4 | last_name_4 | first_name_5 | last_name_5 |
| Table 1 | 9:30:00 | first_name_4 | last_name_4 | first_name_6 | last_name_6 |
Here is my table and the data contained in it:
Table: first
+----------+------+
| first_id | data |
+----------+------+
| 1 | 5 |
| 2 | 6 |
| 3 | 7 |
| 4 | 6 |
| 5 | 7 |
| 6 | 5 |
| 7 | 7 |
| 8 | 6 |
| 9 | 5 |
| 10 | 7 |
+----------+------+
Table: second
+-----------+----------+----------+
| second_id | first_id | third_id |
+-----------+----------+----------+
| 1 | 1 | 2 |
| 2 | 2 | 3 |
| 3 | 3 | 4 |
| 4 | 4 | 2 |
| 5 | 5 | 3 |
| 6 | 6 | 4 |
| 7 | 7 | 2 |
| 8 | 8 | 2 |
| 9 | 9 | 4 |
| 10 | 10 | 4 |
+-----------+----------+----------+
My intention is to get the list of third_ids ordered by data field. Now, I ran the following query for that.
SELECT
third_id, data
FROM
first f JOIN second s ON ( s.first_id = f.first_id )
ORDER BY
data ASC;
And I get the following result as expected.
+----------+------+
| third_id | data |
+----------+------+
| 4 | 5 |
| 2 | 5 |
| 4 | 5 |
| 2 | 6 |
| 3 | 6 |
| 2 | 6 |
| 2 | 7 |
| 4 | 7 |
| 4 | 7 |
| 3 | 7 |
+----------+------+
The following query is also work as expected.
SELECT
third_id
FROM
first f JOIN second s ON ( s.first_id = f.first_id )
ORDER BY
data ASC;
with output
+----------+
| third_id |
+----------+
| 4 |
| 2 |
| 4 |
| 2 |
| 3 |
| 2 |
| 2 |
| 4 |
| 4 |
| 3 |
+----------+
Then I ran the following.
SELECT DISTINCT
third_id
FROM
first f JOIN second s ON ( s.first_id = f.first_id )
ORDER BY
data ASC;
But, here I get an unexpected result:
+----------+
| third_id |
+----------+
| 2 |
| 3 |
| 4 |
+----------+
Here, 3 must be after 2 and 4, since I am ordering on the data field. What am I doing wrong? Or do I have to go for a different strategy.
Note:
This scenario happens on my project. The tables provided here doesn't belong to original database. It is created by me to explain the problem. Original tables contain thousands of rows.
I am inserting database dump if you would like to experiment with the data:
--
-- Table structure for table `first`
--
CREATE TABLE IF NOT EXISTS `first` (
`first_id` int(11) NOT NULL AUTO_INCREMENT,
`data` int(11) NOT NULL,
PRIMARY KEY (`first_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=11 ;
--
-- Dumping data for table `first`
--
INSERT INTO `first` (`first_id`, `data`) VALUES
(1, 5),
(2, 6),
(3, 7),
(4, 6),
(5, 7),
(6, 5),
(7, 7),
(8, 6),
(9, 5),
(10, 7);
--
-- Table structure for table `second`
--
CREATE TABLE IF NOT EXISTS `second` (
`second_id` int(11) NOT NULL AUTO_INCREMENT,
`first_id` int(11) NOT NULL,
`third_id` int(11) NOT NULL,
PRIMARY KEY (`second_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=11 ;
--
-- Dumping data for table `second`
--
INSERT INTO `second` (`second_id`, `first_id`, `third_id`) VALUES
(1, 1, 2),
(2, 2, 3),
(3, 3, 4),
(4, 4, 2),
(5, 5, 3),
(6, 6, 4),
(7, 7, 2),
(8, 8, 2),
(9, 9, 4),
(10, 10, 4);
You probably want to do something like
SELECT third_id
FROM first JOIN second USING (first_id)
GROUP BY third_id
ORDER BY aggregatesomething(data)
that is min(data) or max(data) or whatever.
Doing a SELECT DISTINCT requires the database to order the values in the column(s) as that is the most efficient way to find the distinct values. As far as I'm aware ORDER BY clauses that do not contain columns that are outputted in the query do not get honoured (SQL SERVER won't accept the query) as it is not clear what it would mean to order by something that did not participate.
You may use a subquery -
SELECT DISTINCT third_id FROM (
SELECT
third_id
FROM
first f JOIN second s ON ( s.first_id = f.first_id )
ORDER BY
data ASC
) t;
It will help to select and sort all data firstly, then to select distinct values.
I had this exact problem before. I finally came up with a simple solution, almost seems too simple. You need to use a subquery as a column of the select query. In that subquery is where you will do the ordering by date. When you do it all in a single query with ORDER BY happens before the JOIN. You want to order first, so go with the subquery. http://nathansnoggin.blogspot.com/2009/04/select-distinct-with-order-by.html
I'm struggling to get a final result set for a 3 table hierarchical set of data. Hopefully, the diagrams will indicate what I have and what I'm trying to do. Briefly, my final result set (below) should easily allow me to define a dynamic number of checkboxes in my web site, while also allowing me to define whether the boxes are checked, all from within a single result set. I believe that since the data is normalized, I should be able to get a single result set, but I can't get my head wrapped around this on... Can anyone help??
TABLE A TABLE B TABLE C
MEMBER CONTACT ALERT
(pk)$member_id -> (pk)$contact_id -> (pk)$alert_id
(fk)$member_id (fk)$contact_id
$alert_type ->
-> 'local', 'state', 'nation'
Example of my filter criteria is member_id = 1 AND alert_type = 'local'
* = results of filter member_id = 1
TABLE MEMBERS A
+----------+----------+
|member_id | Name |
+----------+----------+
| 1 | Alan | *
| 2 | Brad |
| 3 | Doug |
| 4 | Flo |
+---------------------+
TABLE CONTACTS B
+--------------------------------------------------------------------+
| contact_id | member_id | email | phone | Name |
+------------+-------------+---------------+--------------+----------+
| 1 | 1 | a#gmail.com | | Alex | *
| 2 | 1 | b#gmail.com | 123-456-7890 | Bob | *
| 3 | 3 | c#gmail.com | | Cris |
| 4 | 1 | d#gmail.com | | Dan | *
| 5 | 2 | e#gmail.com | | Ed |
| 6 | 1 | f#gmail.com | | Fran | *
| 7 | 1 | g#gmail.com | 212-323-1111 | Greg | *
| 8 | 2 | h#gmail.com | | Hans |
| 9 | 3 | i#gmail.com | | Ida |
| 10 | 1 | j#gmail.com | 945-555-1212 | Jeff | *
| 11 | 2 | k#gmail.com | 945-555-1212 | Karl |
| 12 | 3 | l#gmail.com | | Leo |
+--------------------------------------------------------------------+
# = resutls of filter alert_type = 'local'
TABLE CONTACTS_SELECTED C
+-----------------------------------------+
| alert_id | contact_id | alert_type |
+------------+------------+---------------+
| 1 | 1 | local | * #
| 2 | 1 | state | *
| 3 | 3 | state |
| 4 | 5 | local |
| 5 | 5 | state |
| 6 | 6 | nation | *
| 7 | 7 | local | * #
| 8 | 8 | nation |
| 9 | 10 | local | *
| 10 | 12 | state |
+-------------------------+---------------+
REQUIRED OUTPUT
+------------------------------------------------------------------------------------+
|member_id | contract_id | email | phone | Name | alert_type |
+----------+--------------+---------------+--------------+----------+----------------+
| 1 | 1 | a#gmail.com | | Alex | local |
| 1 | 2 | b#gmail.com | 123-456-7890 | Bob | NULL |
| 1 | 4 | d#gmail.com | | Dan | NULL |
| 1 | 6 | f#gmail.com | | Fran | nation |
| 1 | 7 | g#gmail.com | 212-323-1111 | Greg | local |
| 1 | 10 | j#gmail.com | 945-555-1212 | Jeff | local |
+------------------------------------------------------------------------------------+
With this result set, I should be easily able to FOREACH my way through all 6 records and create a checkbox for each record, and flag those records with 'local' as checked. Can anyone help with setting up this complex query?
--
-- Table structure for table `contacts`
--
CREATE TABLE IF NOT EXISTS `contacts` (
`contact_id` int(12) NOT NULL AUTO_INCREMENT,
`member_id` int(12) NOT NULL,
`email` varchar(30) NOT NULL,
`phone` varchar(15) NOT NULL,
`name` varchar(30) NOT NULL,
PRIMARY KEY (`contact_id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=13 ;
--
-- Dumping data for table `contacts`
--
INSERT INTO `contacts` (`contact_id`, `member_id`, `email`, `phone`, `name`) VALUES
(1, 1, 'a#gmail.com', '', 'Alex'),
(2, 1, 'b#gmail.com', '123-456-7890', 'Bob'),
(3, 3, 'c#gmail.com', '', 'Cris'),
(4, 1, 'd#gmail.com', '987-654-3210', 'Dan'),
(5, 2, 'e#gmail.com', '', 'Ed'),
(6, 1, 'f#gmail.com', '', 'Fran'),
(7, 2, 'h#gmail.com', '234-567-8901', 'Hans'),
(8, 3, 'i#gmail.com', '', 'Ida'),
(9, 1, 'g#gmail.com', '', 'Greg'),
(10, 1, 'j#gmail.com', '456-789-0123', 'Jeff'),
(11, 2, 'k#gmail.com', '945-555-1212 ', 'Karl'),
(12, 3, 'l#gmail.com', '', 'Leo');
CREATE TABLE IF NOT EXISTS `contacts_selected` (
`alert_id` int(12) NOT NULL AUTO_INCREMENT,
`contact_id` int(12) NOT NULL,
`alert_type` varchar(6) NOT NULL,
PRIMARY KEY (`alert_id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=12 ;
--
-- Dumping data for table `contacts_selected`
--
INSERT INTO `contacts_selected` (`alert_id`, `contact_id`, `alert_type`) VALUES
(1, 1, 'local'),
(2, 1, 'state'),
(3, 3, 'state'),
(4, 5, 'local'),
(5, 5, 'state'),
(6, 6, 'nation'),
(7, 7, 'local'),
(8, 8, 'nation'),
(9, 10, 'local'),
(10, 12, 'state'),
(11, 1, 'nation');
CREATE TABLE IF NOT EXISTS `alert_types` (
`alert_type` varchar(6) NOT NULL
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
--
-- Dumping data for table `alert_types`
--
INSERT INTO `alert_types` (`alert_type`) VALUES
('local'),
('state'),
('nation');
SOLUTION:
$alert_type = 'local';
// choices are local, state, nation
//
SELECT c.contact_id, c.member_id, c.email, c.phone, c.desc, s.alert_type
FROM contact c
LEFT JOIN contact_select s
ON c.contact_id = s.contact_id
WHERE c.member_id = 1 AND c.contact_id NOT IN
(SELECT cs.contact_id FROM contact_select cs WHERE cs.alert_type = '$alert_type')
GROUP BY c.contact_id
UNION
SELECT * FROM
(SELECT c.contact_id, c.member_id, c.email, c.phone, c.desc, s.alert_type
FROM contact c
LEFT JOIN contact_select s
ON c.contact_id = s.contact_id
WHERE c.member_id = 1
AND s.contact_id
IN (SELECT cs.contact_id FROM contact_select cs WHERE cs.alert_type = '$alert_type')) z
WHERE z.alert_type = '$alert_type'
This should give you your desired output.
SELECT C.member_id, C.contact_id, C.email, C.phone, C.name, S.alert_type
FROM CONTACTS C
LEFT OUTER JOIN CONTACTS_SELECTED S
ON C.contact_id = S.contact_id
WHERE member_id = 1
select member_id, cs.contract_id, c.email, c.phone, c.name, cs.alert_type
FROM contact c
LEFT JOIN contact_selected cs on cs.contact_id = c.contact_id
WHERE c.member_id = 1
Not sure i understand well what do you mean but maybe you're looking for thiS?
I would try this:
select `c`.`contact_id`, `member_id`, `email`, `phone`, `name`, `alert_type` from contacts `c`
left join contacts_selected `s` on `c`.`contact_id` = `s`.`contact_id`
where member_id=1
group by `c`.`contact_id`
However, two points: One, it's not clear to me how you want to narrow the result set to select only one of the alert types. Two, your sample data and your insert statments contain slightly different data. That's not a problem, but it is a little confusing at first.
I have this table, lets call it table one.
+----+---------+-----------------+
| id | link_id | url |
+----+---------+-----------------+
| 1 | 1 | www.example.com |
| 2 | 1 | www.abc.com |
| 3 | 1 | www.test.com |
| 4 | 1 | www.t1.com |
| 5 | 1 | www.newtest.com |
| 6 | 1 | www.testing.com |
| 7 | 1 | www.abc.com |
| 8 | 1 | www.example.com |
| 9 | 1 | www.web1.com |
| 10 | 1 | www.web2.com |
| 11 | 2 | www.dear.com |
| 12 | 2 | www.google.com |
| 13 | 2 | www.flowers.com |
| 14 | 2 | www.yahoo.com |
| 15 | 2 | www.abc.com |
| 16 | 2 | www.dell.com |
| 17 | 2 | www.web.com |
| 18 | 2 | www.example.com |
| 19 | 2 | www.test.com |
| 20 | 2 | www.abc.com |
+----+---------+-----------------+
20 rows in set (0.00 sec)
The link_id is sort the primary identifier in the table. It tells me which urls appear in link 1, link 2 , etc.
What I want to acomplish is:
1. Get all the unique URLs,
2. Show which links the URL belongs to
So an example output would be:
+-----------------+---------+
| url | link_id |
+-----------------+---------+
| www.example.com | 1 |
| www.example.com | 2 |
| www.abc.com | 1 |
| www.abc.com | 2 |
| www.test.com | 1 |
| www.test.com | 2 |
| www.t1.com | 1 |
| www.newtest.com | 1 |
| www.testing.com | 1 |
| www.web1.com | 1 |
...and so on.
So you can see that www.example.com appears twice since it is associated with both links 1 and 2, but web1.com appears only once since it belongs only to link 1.
I have tried several different group by but I only end up scratching my head even more.
Any help is appreciated. Here is the table dump if anyone needs:
CREATE TABLE IF NOT EXISTS `table1` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`link_id` tinyint(3) unsigned DEFAULT NULL,
`url` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=21 ;
INSERT INTO `table1` (`id`, `link_id`, `url`) VALUES
(1, 1, 'www.example.com'),
(2, 1, 'www.abc.com'),
(3, 1, 'www.test.com'),
(4, 1, 'www.t1.com'),
(5, 1, 'www.newtest.com'),
(6, 1, 'www.testing.com'),
(7, 1, 'www.abc.com'),
(8, 1, 'www.example.com'),
(9, 1, 'www.web1.com'),
(10, 1, 'www.web2.com'),
(11, 2, 'www.dear.com'),
(12, 2, 'www.google.com'),
(13, 2, 'www.flowers.com'),
(14, 2, 'www.yahoo.com'),
(15, 2, 'www.abc.com'),
(16, 2, 'www.dell.com'),
(17, 2, 'www.web.com'),
(18, 2, 'www.example.com'),
(19, 2, 'www.test.com'),
(20, 2, 'www.abc.com');
Wouldn't a DISTINCT list work? Does order matter?
SELECT DISTINCT url, link_id
FROM `table1`
ORDER BY 1, 2
Unless I'm misunderstanding the question, it sounds like all you need is a DISTINCT clause:
select distinct url, link_id from table1;
SELECT url, GROUP_CONCAT(link_id)
FROM table1
GROUP
BY url;
That'll give you all the distinct URLs, each with a list of link ids
Select url, link_id
From Table1
Group By url, link_id
select * from table group by link_id,url
Well imho you should group by both link_id and url, and than maybe sort by url so the same urls are together.
SELECT url, link_id FROM table1
ORDER BY url
GROUP BY url, link_id
Unless I'm missing something:
SELECT DISTINCT url, link_id FROM table1;