i'm having some trouble with trying to extract some data from several MySQL tables in a join statement.
My tables and attributes are:
appointment_end_time (table)
appointment_end_time_id (int)(pk)(ai)
appointment_end_date (datetime)
appointment_start_time (table)
appointment_date_id (int)(pk)(ai)
appointment_start_date (datetime)
instructor(table)
instructor_id (int)(pk)(ai)
firstname varchar(45)
lastname varchar(45)
appointment_timetable
appointment_timetable_id int(11) AI PK
instructor_id int(11) FK
appointment_date_id int(11) FK
appointment_end_time_id int(11) FK
SELECT a.appointment_timetable_id, i.instructor_id, ad.appointment_start_date, aet.appointment_end_date
FROM db12405956.appointment_timetable a
JOIN instructor i on i.instructor_id = a.instructor_id
JOIN appointment_start_time ad on ad.appointment_date_id = a.appointment_date_id
JOIN appointment_end_time aet on aet.appointment_end_time_id = a.appointment_end_time_id
ORDER BY a.appointment_timetable_id;
However, this code brings back no rows selected when executed so i'm wondering what i'm doing wrong, any help will be much appreciated
Sample rows:
(appointment_end_time)
appointment_end_time_id appointment_end_date
1 2016-12-26 14:00:00
2 2016-12-24 13:00:00
3 2016-12-26 13:00:00
(appointment_start_time)
appointment_date_id appointment_start_date
1 2016-12-26 15:00:00
2 2016-12-24 16:00:00
3 2016-12-26 15:30:00
instructor_id firstname lastname
1 Sasha Thompson
2 Laura Robinson
3 John Walters
appointment_timetable
appointment_timetable_id instructor_id appointment_date_id appointment_end_time_
1 Blank Blank Blank
2 Blank Blank Blank
3 Blank Blank Blank
What you need is to learn how to diagnose the problem yourself. It is a common problem that a query doesn't return the expected results and you should understand how to break things down to find the issue.
Let's start with your query:
SELECT a.appointment_timetable_id, i.instructor_id, ad.appointment_start_date, aet.appointment_end_date
FROM db12405956.appointment_timetable a
JOIN instructor i on i.instructor_id = a.instructor_id
JOIN appointment_start_time ad on ad.appointment_date_id = a.appointment_date_id
JOIN appointment_end_time aet on aet.appointment_end_time_id = a.appointment_end_time_id
ORDER BY a.appointment_timetable_id;
What you do to break it down is start with the first table and then add the joins (and where conditions although you don't have any here), one at a time until the data problem appears. I find this easiest to do by using select * or select top 1 * (Or top 10 as I usually prefer to see more than one record) instead of the field list because then you don't have to look for the fields that are associated with joins you haven't added in yet.
So start with
SELECT top 10 *
FROM db12405956.appointment_timetable a
Then try
SELECT top 10 *
FROM db12405956.appointment_timetable a
JOIN instructor i on i.instructor_id = a.instructor_id
Then
SELECT top 10 *
FROM db12405956.appointment_timetable a
JOIN instructor i on i.instructor_id = a.instructor_id
JOIN appointment_start_time ad on ad.appointment_date_id = a.appointment_date_id
Finally
SELECT top 10 *
FROM db12405956.appointment_timetable a
JOIN instructor i on i.instructor_id = a.instructor_id
JOIN appointment_start_time ad on ad.appointment_date_id = a.appointment_date_id
JOIN appointment_end_time aet on aet.appointment_end_time_id = a.appointment_end_time_id
ORDER BY a.appointment_timetable_id;
At some point you will see where the records fell out and that is the location of the problem. Then you might need to look at the fields you are joining on and the data in them in your data sets to see why they are not returning any matches. For instance, if you are joining on dates, they may be stored as dates in one table and as varchar in another and date "01/01/2016' is not equal to 'Jan 1, 2016' or sometimes the column has some sort of prefix or suffix not in the other table. Something like PR2345 in one table and 2345 in the other. Sometimes the query is correct and no rows genuinely meet the conditions. This could be because the data is not fully populated yet (think writing a report for a system that is not live yet, no data on completed actions because none have completed yet.) or because the requirement was wrong in some of its assumptions or because there should be no matching records. It could even be a bug in the data entry.
Depending on the nature of the problem, you might need to return all the records or only use select top 1 (since all records are disappearing). Using SELECT * this way will help when you are returning too many or duplicate records as well as sometimes is is the fields not being returning that affect the results set. Note that I am not saying to use SELECT * in your final result set, it is only being used as a diagnostic tool here.
In your case, the problem looks as if it is in the first table. There are blanks for instructor ID and the other fields in your sample, so there is nothing to join on. (You only gave a sample so the rest of the table may not be like this.) If this is a case where the data is not there yet due to the feature that would add it not yet being live, then you can test your query only by adding test data to the table. Be sure to delete this data after you have finished unit testing. If the data should have been there, then you need to look at the insert from the application for a bug.
Related
I have two tables:
match_rating, which have data on a team's performance in a match. There are naturally two tuples for every matchId (since there are two teams to each match). The PK is matchId, teamId.
event, which has information on events during matches. The PK is an autoincremented UID, and it contains the Foreign Keys match_id and subject_team_id as well.
Now I want to create a new view which counts how many times certain events happen in a match, for each team, with fields like this:
But for the life of me I cannot get around the fact that there are 1) two tuples for each match in the match_rating table, and 2) querying the event table on match_id returns events for both teams.
The closest I got was something like this:
SELECT SUM(
CASE
WHEN evt.event_type_id = 101 THEN 1
WHEN evt.event_type_id = 111 THEN 1
WHEN evt.event_type_id = 121 THEN 1
[etc]
END
) AS 'mid_chances',
SUM(
CASE
WHEN evt.event_type_id = 103 THEN 1
WHEN evt.event_type_id = 113 THEN 1
WHEN evt.event_type_id = 123 THEN 1
[etc]
END
) AS 'right_chances',
mr.tactic,
mr.tactic_skill,
mr.bp,
evt.match_id,
evt.subject_team_id
FROM event evt
JOIN match_rating mr
ON evt.match_id = mr.match_id
WHERE evt.event_type_id BETWEEN 100 AND 104 OR
evt.event_type_id BETWEEN 110 AND 114 OR
evt.event_type_id BETWEEN 120 AND 124 OR
[etc]
GROUP BY evt.match_id
ORDER BY `right_chances` DESC
But still, this counts the events twice, reporting 2 events where there was only 1, 6 for 3 events and so on. I have tried grouping on team_id as well (GROUP BY evt.match_id AND team_id) , but that returns only 2 rows with all events counted.
I hope I have made my problem clear, and it should be obvious that I really need a good tip or two.
Edit for clarity (sorry):
Sample data for match_rating table:
Sample data for the event table:
What I would like to see as the result is this:
That is, two tuples for each match, one for each team, where the types of events that team had is summed up. Thanks so much for looking into this!
Update after comments/feedback
OK.. just to confirm, what you want is
Each row of the output represents a team within a match
Other values (other than match_id and team_id) are sums or other aggregations across multiple rows?
If that is the case, then I believe you should be doing a GROUP BY the match_id and team_id. This should cause the correct number of rows to be generated (one for each match_id/team_id combination). You say in your question that you have tried it already - I suggest reviewing it (potentially after also considering the below).
With your data, it appears that the 'event' table also has a field which indicates the team_id. To ensure you only get the relevant team's events, I suggest your join between match_rating and event be on both fields e.g.,
FROM event evt
JOIN match_rating mr
ON evt.match_id = mr.match_id
AND evt.subject_team_id = mr.team_id
Previous answer - does not answer the question (as per later comments)
Just confirming - the issue is that when you run it, for each match it returns 2 rows - one for each team - but you want to do processing on both teams as one row only?
As such, you could do a few things (e.g., self-join the match rating table to itself, with Team1 ratings and Team2 ratings).
Alternatively, you could modify your FROM to have joins to match_rating twice - where the first has the lower ID for the two teams e.g.,
FROM event evt
JOIN match_rating mr_team1
ON evt.match_id = mr_team1.match_id
JOIN match_rating mr_team2
ON evt.match_id = mr_team2.match_id
AND mr_team1.match_id < mr_team2.match_id
Of course, your processing then needs to be modified to take this into account e.g., one row represents a match, and you have a bunch of data for team1 and similar data for team2. You'd then, I assume, compare the data for team1 columns and team2 columns to get some sort of rating etc (e.g., chance for Team1 to win, etc).
I have very limited experience with MySQL past standard queries, but when it comes to joins and relations between multiple tables I have a bit of an issue.
I've been tasked with creating a job that will pull a few values from a mysql database every 15 minutes but the info it needs to display is pulled from multiple tables.
I have worked with it for a while to figure out the relationships between everything for the phone system and I have discovered how I need to pull everything out but I'm trying to find the right way to create the job to do the joins.
I'm thinking of creating a new table for the info I need, with columns named as:
Extension | Total Talk Time | Total Calls | Outbound Calls | Inbound Calls | Missed Calls
I know that I need to start with the extension ID from my 'user' table and match it with 'extensionID' in my 'callSession'. There may be multiple instances of each extensionID but each instance creates a new 'UniqueCallID'.
The 'UniqueCallID' field then matches to 'UniqueCallID' in my 'CallSum' table. At that point, I just need to be able to say "For each 'uniqueCallID' that is associated with the same 'extensionID', get the sum of all instances in each column or a count of those instances".
Here is an example of what I need it to do:
callSession Table
UniqueCallID | extensionID |
----------------------------
A 123
B 123
C 123
callSum table
UniqueCallID | Duration | Answered |
------------------------------------
A 10 1
B 5 1
C 15 0
newReport table
Extension | Total Talk Time | Total Calls | Missed Calls
--------------------------------------------------------
123 30 3 1
Hopefully that conveys my idea properly.
If I create a table to hold these values, I need to know how I would select, join and insert those things based on that diagram but I'm unable to construct the right query/statement.
You simply JOIN the two tables, and do a group by on the extensionID. Also, add formulas to summarize and gather the info.
SELECT
`extensionID` AS `Extension`,
SUM(`Duration`) AS `Total Talk Time`,
COUNT(DISTINCT `UniqueCallID`) as `Total Calls`,
SUM(IF(`Answered` = 1,0,1)) AS `Missed Calls`
FROM `callSession` a
JOIN `callSum` b
ON a.`UniqueCallID` = b.`UniqueCallID`
GROUP BY a.`extensionID`
ORDER BY a.`extensionID`
You can use a join and group by
select
a.extensionID
, sum(b.Duration) as Total_Talk_Time
, count(b.Answered) as Total_Calls
, count(b.Answered) -sum(b.Answered) as Missed_calls
from callSession as a
inner join callSum as b on a.UniqueCallID = b.UniqueCallID
group by a.extensionID
This should do the trick. What you are being asked to do is to aggregate the number of and duration of calls. Unless explicitly requested, you do not need to create a new table to do this. The right combination of JOINs and AGGREGATEs will get the information you need. This should be pretty straightforward... the only semi-interesting part is calculating the number of missed calls, which is accomplished here using a "CASE" statement as a conditional check on whether each call was answered or not.
Pardon my syntax... My experience is with SQL Server.
SELECT CS.Extension, SUM(CA.Duration) [Total Talk Time], COUNT(CS.UniqueCallID) [Total Calls], SUM(CASE CS.Answered WHEN '0' THEN SELECT 1 ELSE SELECT 0 END CASE) [Missed Calls]
FROM callSession CS
INNER JOIN callSum CA ON CA.UniqueCallID = CS.UniqueCallID
GROUP BY CS.Extension
I have the following schema in MySQL (read only permissions database)
http://sqlfiddle.com/#!9/1eafc/1
As you can see there are only 5 country codes:
GB, USA, GR, ES, DE
Some months some of the records might not contain one of the countries because no record was created for this country that month.
As you can see in the sqlfiddle, GB records were only created in September.
Is there any way if there isn't any record for a country in that month, instead of not being returned, to show 0 or NULL or something?
I've tried so far different variations of ISNULL, IFNULL and COALESCE but none of them worked.
I want to return something like the following
UK 0
USA 13
GR 5
ES 12
DE 1
Any ideas?
Ok, so in lieu of a functional SQLFiddle I will make a few assumptions. The country code exists in the same table as the grouped data.
If that is the case, why not use:
select DT1.CountryCode, count(DT2.ValueForCounting) as ReturnedCount
from (
select distinct CountryCode
from DataTable ) DT1
left join DataTable DT2
on DT1.CountryCode = DT2.CountryCode
and DT2.QueryConditions = 'Stuff' -- Use the join condition instead of a where clause for anything to do with DT2
your fiddle link not loading,
but i guess my two different ideas about that,
create function and manage it using if condition.
or
create view among month, country and mapping table and put month on left join
hope it works.
We have an iPhone app that sends invoice data by each of our employees several times per day. When they are in low cell signal areas tickets can come in as duplicates, however they are assigned a unique 'job id' in the mysql database, so they're viewed as unique. I could exclude the job id and make the rest of the columns DISTINCT, which gives me the filtered rows I'm looking for (since literally every data point is identical except for the job id), however I need the job ID since it's the primary reference point for each invoice and is what I point to for: approvals, edits, etc.
So my question is, how can I filter out 'near' duplicate rows in my query, while still pulling in the job id for each ticket?
The current query is below:
SELECT * FROM jobs, users
WHERE jobs.job_csuper = users.user_id
AND users.user_email = '".$login."'
AND jobs.job_approverid1 = '0'
Thanks for looking into it!
Edit (examples provided):
This is what I meant by 'near duplicate'
Job_ID - Job_title - Job_user - Job_time - Job_date
2345 - Worked on circuits - John Smith - 1.50 - 2013-01-01
2344 - Worked on circuits - John Smith - 1.50 - 2013-01-01
2343 - Worked on circuits - John Smith - 1.50 - 2013-01-01
So everything is identical except for the Job_ID column.
You want a group by:
SELECT *
FROM jobs, users
WHERE jobs.job_csuper = users.user_id
AND users.user_email = '".$login."'
AND jobs.job_approverid1 = '0'
group by <all fields from jobs except jobid>
I think the final query should look something like this:
select min(Job_ID) as JobId, Job_title, user.name as Job_user, Job_time, Job_date
FROM jobs join users
on jobs.job_csuper = users.user_id
WHERE jusers.user_email = '".$login."' AND jobs.job_approverid1 = '0'
group by Job_title, user.name, Job_time, Job_date
(This uses ANSI syntax for joins and is explicit about the fields coming back.)
It's better to prevent the double submission.
Given that you cannot prevent the double submission...
I would query like this:
select
min(Job_ID) as real_job_id
,count(Job_ID) as num_dup_job_ids
,group_concat(Job_ID) as all_dup_job_ids
,j.Job_title, j.Job_user, j.Job_time, j.Job_date
from
jobs j
inner join users u on u.user_id = j.job_csuper
where
whatever_else
group by
j.Job_title, j.Job_user, j.Job_time, j.Job_date
That includes more than you explicitly asked for. But it's probably good to be reminded of how many dups you have, and it gives you easy access to the duplicate id info when you need it.
How about creating a hash for each row and comparing them:
`SHA1(concat_ws(field1, field2, field3, ...)) AS jobhash`
I have a custom shop, and I need to redo the shipping. However, that is sometimes later, and in the meantime, I need to add a shipping option for when a cart only contains a certain range of products.
SO there is a ship_method table
id menuname name zone maxweight
1 UK Standard ukfirst 1 2000
2 UK Economy uksecond 1 750
3 Worldwide Air world_air 4 2000
To this I have added another column prod_restrict which is 0 for the existing ones, and 1 for the restricted ones, and a new table called ship_prod_restrict which contains two columns, ship_method_id and item_id, listing what products are allowed in a shipping category.
So all I need to do is look in my transactions, and for each cart, just check which shipping methods are either prod_restrict of 0 or have 1 and have no products in the cart that aren't in the restriction table.
Unfortunately it seems that because you can't values from an outer query to an inner one, I can't find a neat way of doing it. (edited to show the full query due to comments below)
select ship_method.* from ship_method, ship_prod_restrict where
ship_method.`zone` = 1 and prod_restrict='0' or
(
prod_restrict='1'
and ship_method.id = ship_prod_restrict.ship_method_id
and (
select count(*) from (
select transactions.item from transactions
LEFT JOIN ship_prod_restrict
on ship_prod_restrict.item_id = transactions.item
and ship_prod_restrict.ship_method_id=XXXXX
where transactions.session='shoppingcartsessionid'
and item_id is null
) as non_permitted_items < 1 )
group by ship_method.id
gives you a list of whether the section matches or not, and works as an inner query but I can't get that ship_method_id in there (at XXXXX).
Is there a simple way of doing this, or am I going about it the wrong way? I can't currently change the primary shipping table, as this is already in place for now, but the other bits can change. I could also do it within PHP but you know, that seems like cheating!
Not sure how the count is important, but this might be a bit lighter - hard to tell without a full table schema dump:
SELECT COUNT(t.item) FROM transactions t
INNER JOIN ship_prod_restrict r
ON r.item_id = t.item
WHERE t.session = 'foo'
AND r.ship_method_id IN (**restricted, id's, here**)