On my website, I have a method that allows a logged in user to mark articles as a favourite, when logged in the articles are highlighted as being saved as a favourite, however if the user has no favourites, I cannot get the query to return any data, what is wrong with my query?
SELECT `job_id`,
COUNT(jobs.job_id) as jobs,
`employers`.`employer_id`,
`logo_small`, `logo_large`,
`company_name`, `job_tags`,
`favourite_employers`.`employer_id` AS employer
FROM (`employers`)
LEFT JOIN `jobs` ON `employers`.`employer_id` = `jobs`.`employer_id`
JOIN `favourite_employers` ON `favourite_employers`.`employer_id` = `jobs`.`employer_id`
WHERE `favourite_employers`.`user_id` = '2'
GROUP BY `jobs`.`employer_id`
ORDER BY `jobs`.`job_id` DESC
use LEFT JOIN instead of JOIN for the favourite_employers table
I know this may seem silly, but did you end the query with a ;?
It would be good to see the DB schema but you probably need a LEFT JOIN for favourite_employers.
The reason could be because this join:
JOIN `favourite_employers` ON `favourite_employers`.`employer_id` = `jobs`.`employer_id`
is returning nothing because there is no favorites
Related
Good day,
I have a small issue with MySQL Distinct.
Trying the following query in my system :
SELECT DISTINCT `booking_id`, `booking_ticket`, `booking_price`, `bookingcomment_id`, `bookingcomment_message` FROM `mysystem_booking`
LEFT JOIN `mysystem_bookingcomment` ON `mysystem_booking`.`booking_id` = `mysystem_bookingcomment`.`bookingcomment_link`
WHERE `booking_id` = 29791
The point is that there are bookings like 29791 that have many comments added.
Let's say 10. Then when running the above query I see 10 results instead of one.
And that's not the way DISTINCT supposes to work.
I simply want to know if there are any comments. If the comment ID is not 0 then there is a comment. Of course I can add COUNT(blabla) as comment_number but that's a whole different story. For me now I'd like just to have this syntax right.
You may try aggregating here, to find which bookings have at least a single comment associated with them:
SELECT
b.booking_id,
b.booking_ticket,
b.booking_price
FROM mysystem_booking b
LEFT JOIN mysystem_bookingcomment bc
ON b.booking_id = bc.bookingcomment_link
WHERE
b.booking_id = 29791
GROUP BY
b.booking_id
HAVING
COUNT(bc.bookingcomment_link) > 0;
Note that depending on your MySQL server mode, you might have to also add the booking_ticket and booking_price columns to the GROUP BY clause to get the above query to run.
You can try below - using a case when expression
SELECT DISTINCT `booking_id`, `booking_ticket`, `booking_price`, `bookingcomment_id`,
case when `bookingcomment_message`<>'0' then 'No' else 'Yes' end as comments
FROM `mysystem_booking`
LEFT JOIN `mysystem_bookingcomment` ON `mysystem_booking`.`booking_id` = `mysystem_bookingcomment`.`bookingcomment_link`
WHERE `booking_id` = 29791
I've been trying to do a subquery where I get all the messages sent by a user and all the recipients of those messages. But the only thing that I can get so far is an error.
This is my query:
SELECT
UR.NAME,
UR.SURNAME,
UR.EMAIL,
UR.PASSWORD,
UR.ADRESS,
UR.CELLPHONE,
UR.COUNTRY,
UR.STATE,
UR.CITY
FROM USERS AS UR
JOIN RECIPIENTBYMESSAGE AS RBM ON RBM.IDRECIPIENT = USERS.IDUSER
WHERE M.IDMESSAGE IN
( SELECT M.IDMESSAGE,
M.BODY,
M.SUBJECT,
US.NAME,
US.SURNAME,
US.EMAIL,
US.PASSWORD,
US.ADRESS,
US.CELLPHONE,
US.COUNTRY,
US.STATE,
US.CITY
FROM MESSAGES AS M
JOIN USERS AS US ON US.IDUSER=M.IDSENDER
WHERE M.IDSENDER=1 );
The problem is in
WHERE M.IDMESSAGE IN
because M.IDMESSAGE is part of the subquery and I'm calling it from outside
but I don't know what should I do.
If someone have any idea, or any other way not necessarily using subqueries I'll be really thankful.
Here are my tables
The
M.IDMESSAGE IN
is not in your select table. You can put there one of the columns in your select that you expect it to match
M.IDMESSAGE
from your
inner select.
I have 2 tables:
table 1:userdetails with fields:uid,mobile,name
table 2:accountdetails with fields:uid,savings,balance
Where uid is common and primary key in both tables.
Now Iam trying to get mobile,savings values from both tables where uid =1 how can we get.I tried below but didnt worked.
select mobile,savings
from userdetails,accountdetails
where userdetails.uid='1'AND
userdetails.uid = accountdetails.uid
Please can some one help
More modern version using the JOIN syntax:
SELECT
a.`mobile`,
b.`savings`
FROM `userdetails` a
JOIN `accountdetails` b
ON a.`uid` = b.`uid`
WHERE a.`uid` = 1
The query should probably look like this:
select ud.mobile, ad.savings
from userdetails ud left join
accountdetails ad
on ud.uid = ad.uid
where ud.uid = 1;
Notes:
Use proper, explicit JOIN syntax.
Use meaningful table aliases and qualify all columns names.
The left join keeps all rows, even if there is no match in the second table. That might be your problem.
I am assuming that uid is actually a number. Don't put numbers around numeric constants.
You could turn on your error display to show you exactly what line is causing the issue.
ini_set('display_errors', 1);
You can try this.
SELECT `ud`.`mobile`, `ad`.`savings`
FROM `userdetails` `ud`
INNER JOIN `accountdetails` `ad` ON `ud`.`uid` = `ad`.`uid`
WHERE `us`.`uid` = 1
Use join
select mobile,savings
from userdetails join accountdetails on userdetails.uid = accountdetails.uid
where userdetails.uid='1'
I am currently running this SQL
SELECT jm_recipe.name, jm_recipe.slug
FROM jm_recipe
LEFT JOIN jm_category_recipe ON jm_category_recipe.recipe_id = jm_recipe.id
WHERE jm_category_recipe.category_id = $cat"
This returns the desired results except that I also need to return the name of the category that the recipe I am looking for is in, to do this I tried to add the field in to my SELECT statement and also add the table into the FROM clause,
SELECT jm_recipe.name, jm_recipe.slug, jm_category_name
FROM jm_recipe, jm_category
LEFT JOIN jm_category_recipe ON jm_category_recipe.recipe_id = jm_recipe.id
WHERE jm_category_recipe.category_id = $cat"
However this just returns no results, what am i doing wrong?
You need to join both tables:
SELECT jm_recipe.name, jm_recipe.slug, jm.category_name
FROM jm_recipe
INNER JOIN jm_category_recipe ON jm_category_recipe.recipe_id = jm_recipe.id
INNER JOIN jm_category ON jm_recipe.recipe_id = jm_category.recipe_id
WHERE jm_category_recipe.category_id = $cat
I've changed the joins to inner joins as well. You might want to make them both LEFT joins if you have NULLs and want them in the result.
Also, you're vulnerable to SQL Injection by simply copying over $cat.
Here's some PHP specific info for you (I'm assuming you're using PHP.)
This small SQL error is bugging me. It doesn't seem to be a problem with the query, just the scope(?), examples work best:
SELECT ocp.*, oc.*, GROUP_CONCAT( u.username SEPARATOR ', ') AS `memjoined`
FROM gangs_ocs_process ocp, gangs_ocs oc
LEFT JOIN users u ON u.userid IN ( ocp.membersin )
WHERE ocp.ocid =1 AND ocp.gangid =1 AND oc.oc_name = ocp.crimename
GROUP BY ocp.ocid
LIMIT 0 , 30
Theres a column (gangs_ocs_process.membersin) which has a list of IDs that have joined (ie 1,2,5). I'm trying to get the usernames for each of these IDs (from the users table) in one go.
The problem is LEFT JOIN users u ON u.userid IN ( ocp.membersin )
If I substitue 1,2,4 in for ocp.membersin (putting the literal list instead of column name), it works ok. It returns a column that has the usernames (image). However, if I leave in the ocp.membersin, I get this error:
#1054 - Unknown column 'ocp.membersin' in 'on clause'
This is the first time I've even used IN in left joins so I'm a bit lost.
Any help would be great :)
I don't think that "IN" will work for this syntax. MySQL expects IN to be something akin to a dataset, not a delimited string. I think you need to find a way to take membersin, expand it into a dataset MySQL can work with (maybe a temporary table), and join on that.
If you have delimited strings in your table, you have a design problem in your database. Add a new table to hold these values.
Are you sure 'membersin' is in the 'gangs_ocs_process' table, and not the 'gangs_ocs' table?
The reason you can't get it to work is because first you need to get your database NORMALIZED. You should NEVER, EVER have a list of ID's in a single column.
After taking another look, I think your problem is trying to aggregate at the wrong point as well as the IN syntax and that you should aggregate in a subquery restricted by the contents of the IN. I don't know enough about your schema to make this out of the box correct, but you want something like this. SomeKeyfield should relate back to gangs_ocs_process
SELECT ocp.*, oc.*, u.Memjoined
FROM gangs_ocs_process ocp, gangs_ocs oc
LEFT JOIN (Select SomeKeyField, GROUP_CONCAT( u.username SEPARATOR ', ') as memjoined
from users where userid in
(select membersin from gangs_ocs_process
where [whatever conditions] )
Group By SomeKeyField) u on ocp.SomeKeyField = u.SomeKeyField
WHERE ocp.ocid =1 AND ocp.gangid =1 AND oc.oc_name = ocp.crimename
GROUP BY ocp.ocid
LIMIT 0 , 30
This is a bad way to keep membership.
But if you still need to live with it, you may try REGEXP matching to test for membership:
SELECT ocp.*, oc.*, GROUP_CONCAT( u.username SEPARATOR ', ') AS `memjoined`
FROM gangs_ocs_process ocp
LEFT JOIN users u ON (ocp.membersin RLIKE CONCAT('(^|,)[[:blank:]]?', userid, '[[:blank:]]?($|,)'))
JOIN gangs_ocs oc ON (ocp.ocid = 1 AND ocp.gangid = 1 AND oc.oc_name = ocp.crimename)
GROUP BY ocp.ocid
LIMIT 0 , 30