I am running a SQL query to obtain results with the column applicationstatus that aren't S to tell which position is still open. There are 3 application status U=Unsuccessful, O = ongoing and S = successful. This works fine. Below is the code I am running.
SELECT DISTINCT position.position_ID, Title, EmployerName, Industry
FROM position
JOIN application ON position.position_id = application.position_id
JOIN employer ON position.employer_id = employer.employer_id
WHERE applicationstatus != 'S'
The problem I am facing is with the above query code, let's assume position_ID 3212 has received 3 applications, with one successful application; I get 2 results for the mentioned position(Excluding the successful one) like this.
Is there a way to filter it so that if a position already has a successful application, then the rows with the same position ID will be ignored?
Add a NOT EXISTS condition to exclude positions with successful applications:
SELECT DISTINCT
p.position_ID,
Title,
EmployerName,
Industry
FROM position p
JOIN application a
ON p.position_id = a.position_id
JOIN employer e
ON p.employer_id = e.employer_id
WHERE
applicationstatus != 'S'
AND NOT EXISTS(
SELECT 1
FROM application
WHERE
position_id = a.position_id
AND applicationstatus = 'S'
)
Note that I've rewritten your query to use meaningful aliases. You should also do this to improve readability and maintainability of your code.
Related
Overview
I have two tables as can be seen below:
user_planes
----------------------------------
|id |user_id|plane_id|fuel|status|
----------------------------------
| 2 1 1 1 Ready |
----------------------------------
shop_planes
------------------------
|id |name|fuel_capacity|
------------------------
| 1 bob 3 |
------------------------
Foreign Key Primary Key
user_planes.plane_id <-> shop_planes.id
I want to be able to get every field (SELECT *) in user_planes and name and fuel_capacity based on the following criteria:
WHERE user_planes.user_id = ? - Parameter which will be added to the query through PHP.
WHERE user_planes.status = 'Ready'
WHERE user_planes.fuel < shop_planes.fuel_capacity
The Issue and My Attempts
I've tried JOIN however it retrieves data which doesn't fit that criteria, meaning it gets extra data which is from shop_planes and not user_planes.
SELECT * FROM `user_planes` WHERE fuel IN (SELECT shop_planes.fuel_capacity FROM shop_planes WHERE fuel < shop_planes.fuel_capacity) AND user_planes.user_id = 1 AND status = 'Ready'
and
SELECT * FROM `user_planes` INNER JOIN `shop_planes` ON user_planes.fuel < shop_planes.fuel_capacity AND user_planes.user_id = 1 AND user_planes.status = 'Ready'
I've searched Stackoverflow and looked through many questions but I've not been able to figure it.
I've looked up many tutorials but still can't get the desired result.
The desired result is that the query should use the data stored in user_planes to retrieve data from shop_planes while at the same time not getting any excess data from shop_planes.
Disclaimer
I really struggle using JOIN queries, I could use multiple separate queries however I wish to optimise my queries hence I'm trying to bring it in to one query.
If their isn't clarity in the question, please do say, I'll update it to the best of my ability.
Note - Is there an easy query builder option available either through phpmyadmin or an alternative software?
Thanks in advance.
Your last attempt was not a bad one, the only thing you missed there was the join criteria you described at the beginning of your post. I also moved the other filters to the where clause to better distinguish between join condition and the filters.
SELECT `user_planes`.*
FROM `user_planes`
INNER JOIN `shop_planes` ON user_planes.plane_id = shop_planes.id
WHERE user_planes.fuel < shop_planes.fuel_capacity AND user_planes.user_id = 1 AND user_planes.status = 'Ready'
First you need the base JOIN
SELECT up.* -- only user_plane fields
FROM shop_planes sp -- CREATE alias for table or field
JOIN user_planes up
ON sp.id = up.plane_id
Case 1: apply a filter in where condition with php parameter.
SELECT up.*
FROM shop_planes sp
JOIN user_planes up
ON sp.id = up.plane_id
WHERE up.user_id = ?
Case 2: apply a filter in where condition with string constant
SELECT up.*
FROM shop_planes sp
JOIN user_planes up
ON sp.id = up.plane_id
WHERE user_planes.status = 'Ready'
Case 3: aply filter comparing fields from both tables
SELECT up.*
FROM shop_planes sp
JOIN user_planes up
ON sp.id = up.plane_id
WHERE up.fuel < sp.fuel_capacity
Try something like:
SELECT
up.id AS User_Plane_ID
, up.[user_id]
, up.plane_id
, up.fuel
, up.[status]
, sp.name AS shop_Plane_Name
, sp.fuel_capacity AS shop_Plane_Fuel_Capacity
FROM User_Planes up
INNER JOIN Shop_Planes sp ON up.plane_id = sp.id
AND up.fuel < sp.Fuel_Capacity
WHERE up.[status] = 'Ready'
AND up.[user_id] = ?
Definitely find a tutorial for JOINs, and don't use SELECT *. With SELECT *, you may end up querying much more than you actually need and it can cause problems if the table changes. You'll enjoy your day much more if you explicitly name the columns you want in your query.
I've aliased some of the columns (with AS) since some of those column names may be reserved words. I've also moved the JOIN criteria to include a filter on fuel
http://sqlfiddle.com/#!3/3ec1f/119
Here's my fiddle...I want the result to look like this but the query I'm using doesn't do that:
My problem with the query is that I can't seem to exclude "The Kingdom of the Crystal Skull" using the exclusion_flag condition. I also don't know why it seems that Contract 3 (Raiders of the Lost Arc) is not showing up either. I have been toiling with this for hours and have no idea what the problem is. I tried looking into subqueries, but I'm not sure that's the solution...
There's a couple of questions/issues there so I'll try to address them individually.
1) You can't exclude "The Kingdom of the Crystal Skull" using the exclusion_flag because contract_sid 7 and 8 both refer to product_list_sid 3 which includes "The Kingdom of the Crystal Skull" - you would need to create a separate product_list_sid if you wanted a contract which excluded it.
2) "Raiders of the Lost Arc" (contract_sid 3) isn't showing up because it's a "single product" contract, and your query only joins from scope to product_list_join using product_list_id - contract_sid 3 is in the product_sid column so you need a separate join to cater for contracts that use product_sid instead of product_list_sid (I assume that a contract can't use both). This is a pretty dodgy schema design but here's a query that solves that issue. Notice the use of LEFT OUTER JOIN to indicate that the table being joined to might not contain any rows (for example when scope.product_list_sid is NULL but scope.product_sid is not).
SELECT s.contract_sid,
c.contract_description,
ISNULL(p.product_description, p2.product_description) AS product_description
FROM scope s
JOIN contracts c ON (c.contract_sid = s.contract_sid)
LEFT OUTER JOIN
product_list_join plj ON (plj.product_list_sid = s.product_list_sid)
LEFT OUTER JOIN
products p ON (p.product_sid = plj.product_sid)
LEFT OUTER JOIN
products p2 ON (p2.product_sid = s.product_sid)
WHERE s.exclusion_flag = 'N'
ORDER BY s.contract_sid;
Here's the SQLFiddle for my solution: http://sqlfiddle.com/#!3/fc62e/10
Edit: After posting this I realised what you're actually trying to do - the scope table not only provides the details of contracts but also provides specific products to exclude from contracts. Again, this is bad schema design and there should be a separate scope_exclusions table or something, but here's a query that does that and excludes "The Kingdom of the Crystal Skull" as requested:
SELECT inner_query.contract_description,
inner_query.product_description
FROM (
SELECT s.contract_sid,
c.contract_description,
ISNULL(p.product_sid, p2.product_sid) AS product_sid,
ISNULL(p.product_description, p2.product_description) AS product_description
FROM scope s
JOIN contracts c ON (c.contract_sid = s.contract_sid)
LEFT OUTER JOIN
product_list_join plj ON (plj.product_list_sid = s.product_list_sid)
LEFT OUTER JOIN
products p ON (p.product_sid = plj.product_sid)
LEFT OUTER JOIN
products p2 ON (p2.product_sid = s.product_sid)
WHERE s.exclusion_flag = 'N'
) inner_query
WHERE NOT EXISTS ( SELECT 1
FROM scope
WHERE exclusion_flag = 'Y'
AND contract_sid = inner_query.contract_sid
AND product_sid = inner_query.product_sid )
ORDER BY inner_query.contract_description;
SQL Fiddle: http://sqlfiddle.com/#!3/fc62e/14
I know this has been asked plenty times before, but I cant find an answer that is close to mine.
I have the following query:
SELECT c.cases_ID, c.cases_status, c.cases_title, ci.custinfo_FName, ci.custinfo_LName, c.cases_timestamp, o.organisation_name
FROM db_cases c, db_custinfo ci, db_organisation o
WHERE c.userInfo_ID = ci.userinfo_ID AND c.cases_status = '2'
AND organisation_name = (
SELECT organisation_name
FROM db_sites s, db_cases c
WHERE organisation_ID = '111'
)
AND s.sites_site_ID = c.sites_site_ID)
What I am trying to do is is get the cases, where the sites_site_ID which is defined in the cases, also appears in the db_sites sites table alongside its organisation_ID which I want to filter by as defined by "organisation_ID = '111'" but I am getting the response from MySQL as stated in the question.
I hope this makes sense, and I would appreciate any help on this one.
Thanks.
As the error states your subquery returns more then one row which it cannot do in this situation. If this is not expect results you really should investigate why this occurs. But if you know this will happen and want only the first result use LIMIT 1 to limit the results to one row.
SELECT organisation_name
FROM db_sites s, db_cases c
WHERE organisation_ID = '111'
LIMIT 1
Well the problem is, obviously, that your subquery returns more than one row which is invalid when using it as a scalar subquery such as with the = operator in the WHERE clause.
Instead you could do an inner join on the subquery which would filter your results to only rows that matched the ON clause. This will get you all rows that match, even if there is more than one returned in the subquery.
UPDATE:
You're likely getting more than one row from your subquery because you're doing a cross join on the db_sites and db_cases table. You're using the old-style join syntax and then not qualifying any predicate to join the tables on in the WHERE clause. Using this old style of joining tables is not recommended for this very reason. It would be better if you explicitly stated what kind of join it was and how the tables should be joined.
Good pages on joins:
http://dev.mysql.com/doc/refman/5.0/en/join.html (for the right syntax)
http://www.codinghorror.com/blog/2007/10/a-visual-explanation-of-sql-joins.html (for the differences between the types of joins)
I was battling this for an hour, and overcomplicated it completely. Sometimes a quick break and writing it out on an online forum can solve it for you ;)
Here is the query as it should be.
SELECT c.cases_ID, c.cases_status, c.cases_title, ci.custinfo_FName, ci.custinfo_LName, c.cases_timestamp, c.sites_site_ID
FROM db_cases c, db_custinfo ci, db_sites s
WHERE c.userInfo_ID = ci.userinfo_ID AND c.cases_status = '2' AND (s.organisation_ID = '111' AND s.sites_site_ID = c.sites_site_ID)
Let me re-write what you have post:
SELECT
c.cases_ID, c.cases_status, c.cases_title, ci.custinfo_FName, ci.custinfo_LName,
c.cases_timestamp, c.sites_site_ID
FROM
db_cases c
JOIN
db_custinfo ci ON c.userInfo_ID = ci.userinfo_ID and c.cases_status = '2'
JOIN
db_sites s ON s.sites_site_ID = c.sites_site_ID and s.organization_ID = 111
Here is a brief explanation of what I'm trying to accomplish; my query follows below.
There are 4 tables and 1 view which are relevant for this particular query (sorry the names look messy, but they follow a strict convention that would make sense if you saw the full list):
Performances may have many Performers, and those associations are stored in PPerformer. Fans can have favorites, which are stored in Favorite_Performer. The _UpcomingPerformances view contains all the information needed to display a user-friendly list of upcoming performances.
My goal is to select all the data from _UpcomingPerformances, then include one additional column that specifies whether the given Performance has a Performer which the Fan added as their favorite. This involves selecting the list of Performers associated with the Performance, and also the list of Performers who are in Favorite_Performer for that Fan, and intersecting the two arrays to determine if anything is in common.
When I execute the below query, I get the error #1054 - Unknown column 'up.pID' in 'where clause'. I suspect it's somehow related to a misuse of Correlated Subqueries but as far as I can tell what I'm doing should work. It works when I replace up.pID (in the WHERE clause of t2) with a hard-coded number, and yes, pID is an existing column of _UpcomingPerformances.
Thanks for any help you can provide.
SELECT
up.*,
CASE
WHEN EXISTS (
SELECT * FROM (
SELECT RID FROM Favorite_Performer
WHERE FanID = 107
) t1
INNER JOIN
(
SELECT r.ID as RID
FROM PPerformer pr
JOIN Performer r ON r.ID = pr.Performer_ID
WHERE pr.Performance_ID = up.pID
) t2
ON t1.RID = t2.RID
)
THEN "yes"
ELSE "no"
END as pText
FROM
_UpcomingPerformances up
The problem is scope related. The nested Selects make the up table invisible inside the internal select. Try this:
SELECT
up.*,
CASE
WHEN EXISTS (
SELECT *
FROM Favorite_Performer fp
JOIN Performer r ON fp.RID = r.ID
JOIN PPerformer pr ON r.ID = pr.Performer_ID
WHERE fp.FanID = 107
AND pr.Performance_ID = up.pID
)
THEN 'yes'
ELSE 'no'
END as pText
FROM
_UpcomingPerformances up
I've been trying to write a few little plugins for personal use with WHMCS. Essentially what I'm trying to do here is grab a bunch of information about a certain order(s), and return it as an array in Perl.
The Perl bit I'm fine with, it's the MySQL query I've formed that's giving me stress..
I know it's big and messy, but what I have is:
SELECT tblhosting.id, tblhosting.userid, tblhosting.orderid, tblhosting.packageid, tblhosting.server, tblhosting.domain, tblhosting.username, tblorders.invoiceid, tblproducts.gid, tblservers.ipaddress, tblinvoices.status
FROM tblhosting, tblproducts, tblorders, tblinvoices, tblservers
WHERE tblorders.status = 'Pending'
AND tblproducts.gid = '2'
AND tblservers.id = tblhosting.server
AND tblorders.id = tblhosting.orderid
AND tblinvoices.id = tblorders.invoiceid
AND tblinvoices.status = 'Paid'
I don't know if this /should/ work, but I assume I'm on the right track as it does return what I'm looking for, however it returns everything twice.
For example, I created a new account with the domain 'sunshineee.info', and then in PHPMyAdmin ran the above query.
id userid orderid packageid server domain username invoiceid gid ipaddress status
13 7 17 6 1 sunshineee.info sunshine 293 2 184.22.145.196 Paid
13 7 17 6 1 sunshineee.info sunshine 293 2 184.22.145.196 Paid
Could anyone give me a heads up on where I've gone wrong with this one.. Obvioiusly (maybe not obviously enough) I want this as only one row returned per match.. I've tried it with >1 domain in the database and it returned duplicates for each of the matches..
Any help would be much appreciated
:)
SELECT distinct tblhosting.id, tblhosting.userid, tblhosting.orderid, tblhosting.packageid, tblhosting.server, tblhosting.domain, tblhosting.username, tblorders.invoiceid, tblproducts.gid, tblservers.ipaddress, tblinvoices.status
FROM tblhosting, tblproducts, tblorders, tblinvoices, tblservers
WHERE tblorders.status = 'Pending'
AND tblproducts.gid = '2'
AND tblservers.id = tblhosting.server
AND tblorders.id = tblhosting.orderid
AND tblinvoices.id = tblorders.invoiceid
AND tblinvoices.status = 'Paid'
Well, its near impossible without any table definitions, but you are doing a lot of joins there. You are starting with tblhosting.id and working your way 'up' from there. If any of the connected tables has a double entry, you'll get more hits
You could add a DISTINCT to your query, but that would not fix the underlying issue. It could be a problem with your data: do you have 2 invoices? Maybe you should select everything (SELECT * FROM) and check what is returned, maybe check your tables for double content.
Using DISTINCT is most of the time not a good choice: it means either your query or your data is incorrect (or you don't understand them thoroughly). It might get you the right result for now, but can get you in trouble later.
A guess about the reason this happens:
You do not connect the products table to the chain of id's. So you are basically adding a '2' to your result as far as I can see. You join on products, and the only thing that limits that table is that "gid" should be 2. So if you add a product with gid 2 you get another result. Either join it (maybe tblproduct.orderid = tblorders.id ? just guessing here) or just remove it, as it does nothing as far as I can see.
If you want to make your query a bit clearer, try not implicitly joining, but do it like this. So you can actually see what's happening
SELECT tblhosting.id, tblhosting.userid, tblhosting.orderid, tblhosting.packageid, tblhosting.server, tblhosting.domain, tblhosting.username, tblorders.invoiceid, tblproducts.gid, tblservers.ipaddress, tblinvoices.status
FROM tblhosting
JOIN tblproducts ON /*you're missing something here!*/
JOIN tblorders ON tblorders.id = tblhosting.orderid
JOIN tblinvoices ON tblinvoices.id = tblorders.invoiceid
JOIN tblservers ON tblservers.id = tblhosting.server
WHERE
tblorders.status = 'Pending'
AND tblproducts.gid = '2'
AND tblinvoices.status = 'Paid'
I don't see in your query JOIN to tblproducts, it seems to be a reason.