SQL /php LEFT JOIN - Only display one instance - php

I am using the following query which works great but I need a modification to it.
SELECT *
FROM `table1` LEFT JOIN
`table2` ON table1.messageid=table2.messageid
WHERE `venue_active` = 1
My problem here is that I table2.messageid might have more than 1 match and I only what 1 displayed, but I still want all the records on table1 to be returned.
For example:
table1.messageid might have lots of children on Table2 and I only need 1 displayed
How can I do this?
UPDATE: I've tried adding: GROUP BY table1.messageid but it returns nothing.


add a group by clause
SELECT *
FROM `table1` LEFT JOIN
`table2` ON table1.messageid=table2.messageid
WHERE `venue_active` = 1
GROUP BY table1.messageid


just add group by
SELECT *
FROM `table1` LEFT JOIN
`table2` ON table1.messageid=table2.messageid
WHERE `venue_active` = 1
GROUP BY table1.messageid


I don't have your exact tables but this is the equivilent of your query running off a couple of my tables which are 1:many relationships tblusers being your table1 and tblmessages being your table2
SELECT tblusers.ID FROM `tblusers` LEFT JOIN tblmessages ON tblusers.ID=tblmessages.recipient_user_id WHERE tblmessages.state=1
This returns this
If I now change the query to be this
SELECT DISTINCT tblusers.ID FROM `tblusers` LEFT JOIN tblmessages ON tblusers.ID=tblmessages.recipient_user_id WHERE tblmessages.state=1
I now get a unique list of all users which have at least one message in my messages table.

Related

MYSQL/PHP: Concat returning to many fields on LEFT JOIN

I had a SELECT query with a LEFT JOIN working as desired. I then added one more table via a smilar LEFT JOIN and now I am getting a wierd result. Basically, for a group_concat where I was getting one item for every record, I am getting eight records. I don't see why this is happening because the join to the new table is analagous to several other joins that do not have this problem (that I have omitted from the example for clarity).
Here is the query that is fine:
$sql = "SELECT t.*,
group_concat(tf.todoid) as `tftodoid`,
group_concat(tf.id) as `tfid`,
group_concat(tf.filedescript) as `tffiledescript`,
group_concat(tf.filename) as `tffilename`,
group_concat(tf.founderid) as `tffounderid`,
group_concat(tf.ext) as `tfext`,
group_concat(tf.lasttouched) as `tilt`
FROM titles `t`
LEFT JOIN titlefiles `tf`
ON (tf.todoid = t.id AND tf.founderid = '$userid')
WHERE t.userid='$userid'
GROUP BY t.id";
And here is the query with the extra join that is now spilling out the multiple copies of the items:
$sql = "SELECT t.*,
group_concat(tf.todoid) as `tftodoid`,
group_concat(tf.id) as `tfid`,
group_concat(tf.filedescript) as `tffiledescript`,
group_concat(tf.filename) as `tffilename`,
group_concat(tf.founderid) as `tffounderid`,
group_concat(tf.ext) as `tfext`,
group_concat(tf.lasttouched) as `tilt`,
group_concat(s.id) as `stepid`,
group_concat(s.step) as `steps`
FROM titles `t`
LEFT JOIN titlefiles `tf`
ON (tf.titleid = t.id AND tf.founderid = '$userid')
LEFT JOIN steps `s`
ON s.titleid = t.id
WHERE t.userid='$userid'
GROUP BY t.id";
Here is an example of output in JSON showing the difference:
First query:
"tfid":"56,57,58,59,60,61,62,63,64,65,66,67,68,75,76,81"
Second query:
"tfid":"56,57,58,59,60,61,62,63,64,65,66,67,68,75,76,81,56,57,58,59,60,61,62,63,64,65,66,67,68,75,76,81,56,57,58,59,60,61,62,63,64,65,66,67,68,75,76,81,56,57,58,59,60,61,62,63,64,65,66,67,68,75,76,81,56,57,58,59,60,61,62,63,64,65,66,67,68,75,76,81,56,57,58,59,60,61,62,63,64,65,66,67,68,75,76,81,56,57,58,59,60,61,62,63,64,65,66,67,68,75,76,81,56,57,58,59,60,61,62,63,64,65,66,67,68,75,76,81,56,57,58,59,60,61,62,63,64,65,66,67,68,75,76,81",
I suspect the problem has something to do with the JOIN or with the Group By statements but I can't see how to fix.
How can I ensure that I get only one fileid per file as opposed to eight?

Alter the line as follows:
group_concat(DISTINCT tf.id) as `tfid`,
This then only gets you the unique ids.
If you want them ordered add:
group_concat(DISTINCT tf.id ORDER BY tf.id ASC) as `tfid`,

UNION SELECT tables with inner join and GET values with "ALIAS"

So I have 2 tables, Matches and Teams, what I want to do is get some values from the match and Inner join "Teams" to get the names of both teams and add them to a php array later on (getting it all in one sql)
Matches
- IDMatch
- IDLocalTeam
- IDVisitorTeam
- Time
- Half
- Stopped
Teams
- IDTeam
- name
What I have by now is
$query = "SELECT * FROM `Matches`
INNER JOIN `Teams` ON `Matches`.IDLocalTeam = `Teams`.IDTeam
UNION SELECT * FROM `Matches` INNER JOIN `Teams`
ON `Matches`.IDVisitorTeam = `Teams`.IDTeam
ORDER BY IDMatch DESC;";
If someone could help me it would be great! Thanks alot

Wouldn't it be easier to use INNER JOIN twice? It's definitely quicker way of doing joins anyway.
SELECT
*
FROM
`Matches` m
INNER JOIN `Teams` t1
ON m.IDLocalTeam = t1.IDTeam
INNER JOIN `Teams` t2
ON m.IDVisitorTeam = t2.IDTeam
ORDER BY
m.IDMatch DESC;
Also start using aliases instead of table names to identify fields in query, it will SQL much smaller.

How to Match last inserted single column against multiple values in child table using Join

I have one table jobs in my database. and its two child tables. one job_status_detail and job_assigned.
One job may have multiple status like created,started,completed in job_status_detail with one job_id.
One job can assigned to multiple user with job_id in job_assigned.
Now i want all job records with last inserted status in job_status_detail.
I use following query
SELECT * FROM `jobs` as `t`
LEFT OUTER JOIN `job_assigned` as `jobDetail` ON (`jobDetail`.`job_id`=`t`.`id`)
LEFT OUTER JOIN `job_status_detail` as `job` ON (`job`.`job_id`=`t`.`id`) WHERE jobDetail.assign_to=1
Order by job.id
but it gives me whole data. if one job has three entry in job_status_detail, it gives me 3 entries.Not last inserted entry.
Result should like one job with one job status(last inserted).

Here is my solution.
SELECT * FROM `jobs` as `t`
LEFT OUTER JOIN `job_assigned` `jobDetail` ON (`jobDetail`.`job_id`=`t`.`id`)
INNER JOIN (select max(id) id from `job_assigned` group by `job_id`) j ON jobDetail.id=j.id
LEFT OUTER JOIN `job_status_detail` `job` ON (`job`.`job_id`=`t`.`id`)
INNER JOIN (select max(id) id from job_status_detail group by job_id) jsd ON job.id=jsd.id
WHERE jobDetail.assign_to=1

You have to put group by tag
SELECT * FROM `jobs` as `t`
LEFT OUTER JOIN `job_assigned` as `jobDetail` ON (`jobDetail`.`job_id`=`t`.`id`)
LEFT OUTER JOIN `job_status_detail` as `job` ON (`job`.`job_id`=`t`.`id`)
GROUP BY job.job_status Order by job.id

Join but return ALL records from Table

I have the following SQL query:
SELECT * FROM `table1` INNER JOIN `table2` ON table1.messageid=table2.messageid WHERE `venue_active` = 1
The above works fine but it only returns fields where both tables have a messageid field.
My problem is that I need it to return ALL fields from Table1 reguardless if it has a messageid match in table2 or not.
So, in other words I need ALL records to be returned from Table1 and all records from Table2 where there's a messageid that matches both.
How can I do this?

Use a LEFT JOIN rather
SELECT *
FROM `table1` LEFT JOIN
`table2` ON table1.messageid=table2.messageid
WHERE `venue_active` = 1
That said, it will only work if venue_active is also part of table1, and not table2.
Have a look at the different scenarios
SQL Fiddle DEMO

Use a LEFT join rather than INNER
For example:
SELECT * FROM `table1`
LEFT JOIN `table2` ON table1.messageid=table2.messageid
WHERE `venue_active` = 1

Either you need a LEFT JOIN instead, or
a FULL OUTER JOIN workaround for MySQL:
SELECT
a.*,
b.*
FROM
table1 a
LEFT JOIN
table2 b ON a.messageid = b.messageid
WHERE a.venue_active = 1
UNION
SELECT
a.*,
b.*
FROM
table1 a
RIGHT JOIN
table2 b ON a.messageid = b.messageid;
WHERE a.venue_active = 1

PHP SQL Query Fields from Another Table Join

I am trying to get a query using fields from 2 tables.
I need to query Table1 but only Table2 has the variable venue_location that I need to query.
Basically I need to count all records on Table1 where Table1.venue_location = $MyVariable.
Here is what I've put together but I believe I need to use Joins for this?
Table1
- venue_id
Table2
- venue_id,
- venue_location
SELECT * FROM Table1 WHERE table1.venue_id = table2.venue_id and table2.location = '$MyVariable'
How can I do a query for this?

Use the power of join table
SELECT * FROM Table1
JOIN Table2 USING(venue_id)
WHERE table2.location = '$MyVariable'
You can get back the count of rows with mysqli_num_rows() in PHP, or change le select by SELECT COUNT(*) AS nbRow FROM ... and check of value in nbRow column

You can join two tables on venue_id and then group it by venue_id where location is your $MyVariable.
Your final query will look like:
SELECT count(table2.venue_id)
FROM Table1
JOIN Table2 ON table1.venue_id = table2.venue_id
WHERE table2.location = '$MyVariable'
GROUP BY table2.venue_id

try this
SELECT Table1.venue_id, Table2.venue_location FROM Table1 INNER JOIN Table2
ON Table1.venue_id='$MyVariable';

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