Here are my tables:
Table PROGRAMME prg
prg_id
ln1_id
pmt_id
prg_commission
dep_id
Table COMMISSION com
com_id
pmt_id
ln1_id
dep_id
com_commission
Table PROMOTEUR pmt
pmt_id
pmt_txcommission
I need to get the "commission" of the table programme
But when it's null or empty (prg.commission), i need to get the "commission" value from the table "Commission" (com.commission - by the ln1_id, pmt_id and dep_id matching from both table).
If there is no result matching (no result in table COMMISSION where com.ln1_id = prg.ln1_id AND com.pmt_id = prg.ln1_id and com.dep_id = prg.dep_id) i need to get the "Commission" of PROMOTEUR (pmt.commission)
I don't really have idea how to do it in Sql... it would be easier in PHP condition but i have to do it on MySQL because after getting the good value of "Commission" for each of my programmes, i need to ORDER them by ASC...
I'm not sure if i'm easily understandable (english not my native language). Here is an exemple of what i tried (not successfully sadly) because there is a bit too much condition for me !
SELECT prg.commision AS commission, pmt.commission AS commission, com.commission AS commission
FROM (((PROGRAMME prg
LEFT JOIN LOINIVEAU1 ln1 ON ln1.ln1_id = prg.ln1_id)
LEFT JOIN PROMOTEUR pmt ON pmt.pmt_id = prg.pmt_id)
LEFT JOIN COMMISSION com ON com.pmt_id = pmt.pmt_id)
WHERE
CASE prg.comission != null
THEN prg.comission
ELSE CASE com.commission != null
THEN com.commission
ELSE pmt.commission
THEN pmt.commission
ORDER BY commission ASC
Is this what you want:
SELECT COALESCE(prg.commission, com.commission, pmt.commission) resolved_commission
FROM PROGRAMME prg
LEFT JOIN COMMISSION com
ON com.pmt_id = prg.pmt_id
AND com.ln1_id = prg.ln1_id
AND com.dep_id = prg.dep_id
LEFT JOIN PROMOTEUR pmt
ON pmt.pmt_id = prg.pmt_id
ORDER BY resolved_commission
I have taken the following steps:
Removed the LEFT JOIN to LOINIVEAU1 as this does not appear to be necessary
Updated the other LEFT JOIN conditions to reflect those in your description
Used COALESCE to return the first not null value from the comma-separated columns.. this replaces the CASE statement that you have incorrectly placed in the WHERE clause.
Removed the unnecessary parentheses.
As another pointer.. never use != NULL use IS NOT NULL instead.. as it turns out I did not need this in my solution.
UPDATE
Following further information:
SELECT CASE
WHEN prg.commission > 0
AND prg.commissionstart >= CURDATE()
AND prg.commissionend < CURDATE() + INTERVAL 1 DAY
THEN prg.commission
WHEN com.commission > 0
THEN com.commission
WHEN pmt.commission > 0
THEN pmt.commission
ELSE 0 /* Whatever you want, probably 0 */
END resolved_commission
FROM PROGRAMME prg
JOIN PROGRAMME_DEPARTMENT prg_dep
ON prg_dep.prg_id = prg.id /* Guessing the JOIN here */
LEFT JOIN COMMISSION com
ON com.pmt_id = prg.pmt_id
AND com.ln1_id = prg.ln1_id
AND com.dep_id = prg_dep.dep_id
LEFT JOIN PROMOTEUR pmt
ON pmt.pmt_id = prg.pmt_id
AND pmt.commissionstart >= CURDATE()
AND pmt.commissionend < CURDATE() + INTERVAL 1 DAY
ORDER BY resolved_commission
Should get you a little closer..
You could replace x > 0 with x IS NOT NULL and x > 0 in the CASE for added clarity.
I would also seriously consider placing all the commissions in the COMMISSION table with a start and end and replacing prg.commission* and pmt.commission* with a link through an intermediate to this table.. this way you can rid yourself of all the 0 values and use a LEFT JOIN with COALESCE to get the resolved_commission.
PERFORMANCE TWEAKS
Use EXPLAIN [EXTENDED] ... to see how your query is being executed and play around with composite indexing combinations of the following columns on each table:
PROGRAMME: ([id,], pmt_id, ln1_id, commission, commissionstart, commissionend)
PROGRAMME_DEPARTMENT: (pmt_id, ln1_id, dep_id)
COMMISSION: (pmt_id, ln1_id, dep_id, commission)
PROMOTEUR: (pmt_id, commission, commissionstart, commissionend)
Related
I have a stored procedure. A little problematic in terms of performance. I want to improve the performance of the stored procedure, but I could not figure out what to do. There are approximately 3 million records in my database. When I run this query one by one, it's good in performance. But when 150 people run this stored procedure at the same time, there are spikes in the CPU.
As an example, I created my procedure and table structures.
My Stored Procedure:
BEGIN
SELECT ss.car_route from person o
inner join car_time ss on ss.inst_id =o.inst_id
and ss.start_time<=DATE_FORMAT(CURTIME(),'%H:%i') AND ss.finish_time>= date_format(curtime() ,'%H:%i') AND ss.car_id=carid
and ss.days like concat('%',(select WEEKDAY(now())+1),'%')
where (o.car_id=carid or o.back_car_id=carid ) LIMIT 1 into #route_;
select sf.stop_service from car_comp sf
inner join cars s on s.inst_id = sf.id and s.id=carid and s.active=1 limit 1
into #stop_ser;
if #route_ = 1 and #stop_ser=0 THEN
select DISTINCT ss.start_time,ss.finish_time ,o.id,o.name,r.photo, oh.state ,oh.datee,ss.car_route,
ifnull(bh.id,0) AS called,
ifnull(mh.excuse_id,0) AS excuse_id,
ifnull(o.latitude_1,0) AS latitude_1,
ifnull(o.longitude_1,0) AS longitude_1,
ifnull(o.latitude_2,0) AS latitude_2,
ifnull(o.longitude_2,0) AS longitude_2,
case when (ifnull(o.call_notify,0)=1 or ifnull(o.mes_notify,0)=1) then 1 else 0 end AS call_notify ,
ifnull(o.rownumber,0) AS rownumber,
ifnull(o.number_1,0) AS number_1,
ifnull(o.number_2,0) AS number_2,
ifnull(o.brownumber,0) AS brownumber,
ifnull(ROUND(o.notify_meter_1/2),0) AS notify_meter_1,
ifnull(ROUND(o.notify_meter_2/2),0) AS notify_meter_2
from person o
inner join car_time ss on ss.inst_id =o.inst_id and o.car_id=ss.car_id
and ss.start_time<=DATE_FORMAT(CURTIME(),'%H:%i') AND ss.finish_time>= date_format(curtime() ,'%H:%i')
and ss.days like concat('%',(select WEEKDAY(now())+1),'%')
LEFT JOIN notify_records bh ON bh.table_id=o.id AND bh.car_route=#route_
and bh.table_name='person' AND bh.notify=4 AND bh.car_id=o.car_id and bh.date_ >= CURDATE() and bh.date_ < CURDATE() + INTERVAL 1 DAY
left join person_records oh on oh.person_id=o.id
and oh.car_id=o.car_id
and date_format(oh.datee,'%H:%i') >=ss.start_time
and date_format(oh.datee,'%H:%i') <=ss.finish_time
AND oh.car_route= #route_
and
oh.id in(select max(id) from person_records
where date_time >= CURDATE() and date_time < CURDATE() + INTERVAL 1 DAY and car_id = carid and car_id = carid
GROUP by person_id
)
left join inst ok on o.inst_id = ok.id and o.car_id=carid
left join excuse_records mh on mh.person_id=o.id and mh.date_time >= CURDATE() and mh.date_time < CURDATE() + INTERVAL 1 DAY and (mh.car_route=ss.car_route)
left join photo_ r on r.table_id = o.id and r.table_name = 'person'
where
(ss.car_route=o.cars_route_ or o.cars_route_=3) and
o.car_id = carid and o.active=1
AND o.work_time=ss.work_time;
elseif #route_ = 2 and #stop_ser=0 then
select DISTINCT ss.start_time,ss.finish_time ,o.id,o.name,r.photo, oh.state ,oh.datee,ss.car_route,
ifnull(bh.id,0) AS called,
ifnull(mh.excuse_id,0) AS excuse_id,
ifnull(o.latitude_1,0) AS latitude_1,
ifnull(o.longitude_1,0) AS longitude_1,
ifnull(o.latitude_2,0) AS latitude_2,
ifnull(o.longitude_2,0) AS longitude_2,
case when (ifnull(o.call_notify,0)=1 or ifnull(o.mes_notify,0)=1) then 1 else 0 end AS call_notify ,
ifnull(o.rownumber,0) AS rownumber,
ifnull(o.number_1,0) AS number_1,
ifnull(o.number_2,0) AS number_2,
ifnull(o.brownumber,0) AS brownumber,
ifnull(ROUND(o.notify_meter_1/2),0) AS notify_meter_1,
ifnull(ROUND(o.notify_meter_2/2),0) AS notify_meter_2
from person o
inner join car_time ss on ss.inst_id =o.inst_id and o.back_car_id=ss.car_id
and ss.start_time<=DATE_FORMAT(CURTIME(),'%H:%i') AND ss.finish_time>= date_format(curtime() ,'%H:%i')
and ss.days like concat('%',(select WEEKDAY(now())+1),'%')
LEFT JOIN notify_records bh ON bh.table_id=o.id AND bh.car_route=#route_
and bh.table_name='person' AND bh.notify=4 AND bh.car_id=o.back_car_id and bh.date_ >= CURDATE() and bh.date_ < CURDATE() + INTERVAL 1 DAY
left join person_records oh on oh.person_id=o.id
and oh.car_id=o.back_car_id and oh.car_route=2
and date_format(oh.datee,'%H:%i') >=ss.start_time
and date_format(oh.datee,'%H:%i') <=ss.finish_time
AND oh.car_route= #route_
and
oh.id in (select max(id) from person_records
where date_time >= CURDATE() and date_time < CURDATE() + INTERVAL 1 DAY and car_id = carid
GROUP by person_id
)
left join inst ok on o.inst_id = ok.id and o.car_id=carid
left join excuse_records mh on mh.person_id=o.id and mh.date_time >= CURDATE() and mh.date_time < CURDATE() + INTERVAL 1 DAY and (mh.car_route=ss.car_route)
left join photo_ r on r.table_id = o.id and r.table_name = 'person'
where
(ss.car_route=o.cars_route_ or o.cars_route_=3) and
o.back_car_id = carid and o.active=1
AND o.work_time=ss.work_time;
END IF;
end
I have a database example here.
I made my.cnf improvement but still have difficulties with performance. What is wrong with this query? What can I change?
Thank you from now.
Edit:
Server version: 10.1.41-MariaDB - MariaDB Server
I have indexes. I forgot to add indexes while creating test data.
What the heck is this?
ss.days like concat('%',(select WEEKDAY(now())+1),'%')
It can at least be sped up by changing to
ss.days like concat('%',WEEKDAY(now()),'%')
And, won't that lead to checking against 2, 21, 20, 12, ... if the WEEKDAY is "2"?
These might be useful for ss:
(car_id, inst_id, start_time)
(inst_id, car_id, finish_time)
LIMIT 1 without ORDER BY leads to some random row being returned? Is the LIMIT redundant? Or is an ORDER BY needed?
Suggest you get some timings -- It is not obvious which of the SELECTs is chewing up the most CPU.
If the PRIMARY KEY of cars is id, then why test for inst_id and active? Yikes! You don't seem to have a PK for cars! Please verify that every table has a PK.
Redundant:
and car_id = carid
and car_id = carid
Why twice? And what tables are those columns in? Please qualify columns so we can understand what is going on.
When #stop_ser=0, the procedure does nothing? In which case, perform that test first, so you can avoid computing #route.
Change start_time to datatype TIME; then you can get rid of DATE_FORMAT in
and ss.start_time<=DATE_FORMAT(CURTIME(),'%H:%i')
AND ss.finish_time>= date_format(curtime() ,'%H:%i')
Also, beware of the inequality tests, it may lead to some edge cases you did not want.
Don't use (m,n) on FLOAT (eg, float(11,7)); it does rounding that is unnecessary. Also, you can't get 7 decimal places for lat/lng except very near the equator and longitude=0. More on precision: http://mysql.rjweb.org/doc.php/latlng#representation_choices
After you have cleaned up those and provided the requested info, I will take another look.
I'm trying to determine how pervasive a particular mistake is in my database. I'm comparing one field against another, and when that field is greater then the other, I want it to count it. I'm also grouping it by a different statement. The purpose of this query is to determine where there are cases in my data base when one price field is larger then another.
The part of the query that is causing problems is "COUNT(CASE when p.IMAP > p.MSRP = 1 ELSE NULL END)" in the select statement. I put two little stars around it, hoping that'd help highlight where it is.
select b.brandName, b.BrandCode, p.ProductVendorStockNumber, **COUNT(Case When p.IMAP > p.MSRP = 1 ELSE NULL END) as 'Count'**
from products p
join brands b on p.brandID = b.brandID
where b.assignedTo = 'Steve' and p.IMAP > p.MSRP and status = 1
GROUP BY b.BrandName
For the count value You could use sum instead of count adding 1 when the condition is true and 0 when false
In sql for aggregated select the select for columns not in aggregated function and not mentioned in group by is deprecated, in the most recent version of mmysql is not allowed and for the older version the result for these values in unpredicatble so you should in group by then column that you have not in aggregation function in select eg:
select b.brandName
, b.BrandCode
, p.ProductVendorStockNumber
,sum(Case When p.IMAP > p.MSRP THEN 1 ELSE 0 END) as my_count
from products p
join brands b on p.brandID = b.brandID
where b.assignedTo = 'Steve' and p.IMAP > p.MSRP and status = 1
GROUP BY b.BrandName, b.BrandCode, p.ProductVendorStockNumber
or filter the result using the rows without aggregation and a join on the right aggregated rows
I have a table that looks like this:
studentID | subjectID | attendanceStatus | classDate | classTime | lecturerID |
12345678 1234 1 2012-06-05 15:30:00
87654321
12345678 1234 0 2012-06-08 02:30:00
I want a query that reports if a student has been absent for 3 or more consecutive classes. based on studentID and a specific subject between 2 specific dates as well. Each class can have a different time. The schema for that table is:
PK(`studentID`, `classDate`, `classTime`, `subjectID, `lecturerID`)
Attendance Status: 1 = Present, 0 = Absent
Edit: Worded question so that it is more accurate and really describes what was my intention.
I wasn't able to create an SQL query for this. So instead, I tried a PHP solution:
Select all rows from table, ordered by student, subject and date
Create a running counter for absents, initialized to 0
Iterate over each record:
If student and/or subject is different from previous row
Reset the counter to 0 (present) or 1 (absent)
Else, that is when student and subject are same
Set the counter to 0 (present) or plus 1 (absent)
I then realized that this logic can easily be implemented using MySQL variables, so:
SET #studentID = 0;
SET #subjectID = 0;
SET #absentRun = 0;
SELECT *,
CASE
WHEN (#studentID = studentID) AND (#subjectID = subjectID) THEN #absentRun := IF(attendanceStatus = 1, 0, #absentRun + 1)
WHEN (#studentID := studentID) AND (#subjectID := subjectID) THEN #absentRun := IF(attendanceStatus = 1, 0, 1)
END AS absentRun
FROM table4
ORDER BY studentID, subjectID, classDate
You can probably nest this query inside another query that selects records where absentRun >= 3.
SQL Fiddle
This query works for intended result:
SELECT DISTINCT first_day.studentID
FROM student_visits first_day
LEFT JOIN student_visits second_day
ON first_day.studentID = second_day.studentID
AND DATE(second_day.classDate) - INTERVAL 1 DAY = date(first_day.classDate)
LEFT JOIN student_visits third_day
ON first_day.studentID = third_day.studentID
AND DATE(third_day.classDate) - INTERVAL 2 DAY = date(first_day.classDate)
WHERE first_day.attendanceStatus = 0 AND second_day.attendanceStatus = 0 AND third_day.attendanceStatus = 0
It's joining table 'student_visits' (let's name your original table so) to itself step by step on consecutive 3 dates for each student and finally checks the absence on these days. Distinct makes sure that result willn't contain duplicate results for more than 3 consecutive days of absence.
This query doesn't consider absence on specific subject - just consectuive absence for each student for 3 or more days. To consider subject simply add .subjectID in each ON clause:
ON first_day.subjectID = second_day.subjectID
P.S.: not sure that it's the fastest way (at least it's not the only).
Unfortunately, mysql does not support windows functions. This would be much easier with row_number() or better yet cumulative sums (as supported in Oracle).
I will describe the solution. Imagine that you have two additional columns in your table:
ClassSeqNum -- a sequence starting at 1 and incrementing by 1 for each class date.
AbsentSeqNum -- a sequence starting a 1 each time a student misses a class and then increments by 1 on each subsequent absence.
The key observation is that the difference between these two values is constant for consecutive absences. Because you are using mysql, you might consider adding these columns to the table. They are big challenging to add in the query, which is why this answer is so long.
Given the key observation, the answer to your question is provided by the following query:
select studentid, subjectid, absenceid, count(*) as cnt
from (select a.*, (ClassSeqNum - AbsentSeqNum) as absenceid
from Attendance a
) a
group by studentid, subjectid, absenceid
having count(*) > 2
(Okay, this gives every sequence of absences for a student for each subject, but I think you can figure out how to whittle this down just to a list of students.)
How do you assign the sequence numbers? In mysql, you need to do a self join. So, the following adds the ClassSeqNum:
select a.StudentId, a.SubjectId, count(*) as ClassSeqNum
from Attendance a join
Attendance a1
on a.studentid = a1.studentid and a.SubjectId = a1.Subjectid and
a.ClassDate >= s1.classDate
group by a.StudentId, a.SubjectId
And the following adds the absence sequence number:
select a.StudentId, a.SubjectId, count(*) as AbsenceSeqNum
from Attendance a join
Attendance a1
on a.studentid = a1.studentid and a.SubjectId = a1.Subjectid and
a.ClassDate >= a1.classDate
where AttendanceStatus = 0
group by a.StudentId, a.SubjectId
So the final query looks like:
with cs as (
select a.StudentId, a.SubjectId, count(*) as ClassSeqNum
from Attendance a join
Attendance a1
on a.studentid = a1.studentid and a.SubjectId = a1.Subjectid and
a.ClassDate >= s1.classDate
group by a.StudentId, a.SubjectId
),
a as (
select a.StudentId, a.SubjectId, count(*) as AbsenceSeqNum
from Attendance a join
Attendance a1
on a.studentid = a1.studentid and a.SubjectId = a1.Subjectid and
a.ClassDate >= s1.classDate
where AttendanceStatus = 0
group by a.StudentId, a.SubjectId
)
select studentid, subjectid, absenceid, count(*) as cnt
from (select cs.studentid, cs.subjectid,
(cs.ClassSeqNum - a.AbsentSeqNum) as absenceid
from cs join
a
on cs.studentid = a.studentid and cs.subjectid = as.subjectid
) a
group by studentid, subjectid, absenceid
having count(*) > 2
I'm trying to write a SQL query to generate a summary row for the actions performed by a given user in a given period. I have the following relevant table structure:
users
id
team
audit_periods (can be processing, shipping, break, etc)
user_id
period_type (can be "processing", "shipping", etc -- not currently normalized)
started_at
finished_at (can be null for the current period, hence the logic around times below)
audit_tasks
audit_period_id
audit_task_type_id
created_at
score
audit_task_types
name ("scan", "place_in_pallet", etc)
score (seems redundant, but we need to maintain the score that the audit_task received at the time it was performed, as the audit_task_type score can change later)
For each user for a given period, I'd like to create something like the following row of data:
users.id users.email time_spent_processing time_spent_shipping ... number_of_scans number_of_pallets
which would be calculated by figuring out for each user:
What audit_periods fall at least partially in the desired window? (Uses started_at and finished_at.)
How long did a user spend in each type of audit_period? (Should involve group by audit_periods.period_type, I'd imagine.)
What audit_tasks fall within the desired window? (Uses created_at -- not in the code below yet.)
How many of each type of audit_task did a user accomplish during the window? (Joins out to audit_task_type, and likely involves a group by on audit_task_types.name.)
How many points were earned during the time period? (Sums the scores of all the audit_tasks in the window.)
I've exhausted all of the SQL tricks I know (not many) and came up with something like the following:
select
u.id as user_id,
u.email as email,
u.team as team,
ap.period_type as period_type,
att.name,
time_to_sec(
timediff(least("2011-03-17 00:00:00", ifnull(ap.finished_at, utc_timestamp())), greatest("2011-03-16 00:00:00", ap.started_at))
) as period_duration,
sum(at.score) as period_score
from audit_periods as ap
inner join users as u on ap.user_id = u.id
left join audit_tasks as at on at.audit_period_id = ap.id
left join audit_task_types as att on at.audit_task_type_id = att.id
where (ap.started_at >= "2011-03-16 00:00:00" or (ap.finished_at >= "2011-03-17 00:00:00" and ap.finished_at <= "2011-03-17 00:00:00"))
and (ap.finished_at <= "2011-03-17 00:00:00" or (ap.started_at >= "2011-03-16 00:00:00" and ap.started_at <= "2011-03-16 00:00:00"))
and u.team in ("Foo", "Bar")
group by u.id, ap.id, at.id
but this seems to be functionally equivalent to just selecting all of the audit tasks in the end. I've tried some subqueries as well, but to little avail. More directly, this generates something like (skipping less important columns):
user_id | period_type | period_duration | name | score
1 processing 1800s scan 200
1 shipping 1000s place_in_pallet 100
1 shipping 1000s place_in_pallet 100
1 break 500s null null
when I want:
user_id | processing | shipping | break | scan | place_in_pallet | score
1 1800s 1000s 500s 1 2 400
I can easily fetch all of the audit_tasks for a given user and roll them up in code, but I might be fetching hundreds of thousands of audit_tasks over a given period, so it needs to be done in SQL.
Just to be clear -- I'm looking for a query to generate one row per user, containing summary data collected across the other 3 tables. So, for each user, I want to know how much time he spent in each type of audit_period (3600 seconds processing, 3200 seconds shipping, etc), as well as how many of each audit_task he performed (5 scans, 10 items placed in pallet, etc).
I think I have the elements of a solution, I'm just having trouble piecing them together. I know exactly how I would accomplish this in Ruby/Java/etc, but I don't think I understand SQL well enough to know which tool I'm missing. Do I need a temp table? A union? Some other construct entirely?
Any help is greatly appreciated, and I can clarify if the above is complete nonsense.
You will need to break this up into two crosstab queries which give you the information about audit_periods by user and another query that will give you the audit_task information by user and then join that to the Users table. It isn't clear how you want to roll up the information in each of the cases. For example, if a given user has 10 audit_period rows, how should the query roll up those durations? I assumed a sum of the durations here but you might want a min or max or perhaps even an overall delta.
Select U.user_id
, AuditPeriodByUser.TotalDuration_Processing As processing
, AuditPeriodByUser.TotalDuration_Shipping As shipping
, AuditPeriodByUser.TotalDuration_Break As break
, AuditTasksByUser.TotalCount_Scan As scan
, AuditTasksByUser.TotalCount_Place_In_Pallet As place_in_pallet
, AuditTasksByUser.TotalScore As score
From users As U
Left Join (
Select AP.user_id
, Sum( Case When AP.period_type = 'processing'
Then Time_To_Sec(
TimeDiff(
Coalesce(AP.started_at, UTC_TIMESTAMP()), AP.finished_at ) ) )
As TotalDuration_Processing
, Sum( Case When AP.period_type = 'shipping'
Then Time_To_Sec(
TimeDiff(
Coalesce(AP.started_at, UTC_TIMESTAMP()), AP.finished_at ) ) )
As TotalDuration_Shipping
, Sum( Case When AP.period_type = 'break'
Then Time_To_Sec(
TimeDiff(
Coalesce(AP.started_at, UTC_TIMESTAMP()), AP.finished_at ) ) )
As TotalDuration_Break
From audit_periods As AP
Where AP.started_at >= #StartDate
And AP.finished_at <= #EndDate
Group by AP.user_id
) As AuditPeriodByUser
On AuditPeriodByUser.user_id = U.user_id
Left Join (
Select AP.user_id
, Sum( Case When AT.Name = 'scan' Then 1 Else 0 End ) As TotalCount_Scan
, Sum( Case When AT.Name = 'place_in_pallet' Then 1 Else 0 End ) As TotalCount_Place_In_Pallet
, Sum( AT.score ) As TotalScore
From audit_tasks As AT
Join audit_task_types As ATT
On ATT.id = AT.audit_task_type_id
Join audit_periods As AP
On AP.audit_period_id = AP.id
Where AP.started_at >= #StartDate
And AP.finished_at <= #EndDate
Group By AP.user_id
) As AuditTasksByUser
On AuditTasksByUser.user_id = U.user_id
I have two tables. ticket & ticketlist.
The sold out column in the ticket table needs to be 1 if that item is sold out.
Table ticket needs to be soldout when the count for that item in table ticketlist is 2.
ticket
ticketid, quantity, soldout
21 2 1
ticketlist
ticketlistid, ticketid
3 21
4 21
The logic is:
soldout should be '1' if ticket.quantity - (COUNT(ticketlist.ticketlistid) WHERE ticket.ticketid = ticketlist.ticketlistid) > 0
This is the MySQL that I tried
UPDATE ticket
SET soldout = '1'
WHERE quantity - (SELECT ticket.ticketid, COUNT(ticketlist.ticketlistid)
FROM ticket, ticketlist
WHERE ticket.ticketid = ticketlist.ticketid) > '0';
Any help will be appreciated.
In your subselect:
You should only return one column.
Don't select the same table you already have from your update.
You probably also want to set sold_out to one when quantity - (SELECT ...) <= 0, rather than > 0 as you are currently doing.
Change the query to this:
UPDATE ticket
SET soldout = '1'
WHERE quantity - (
SELECT COUNT(ticketlist.ticketlistid)
FROM ticketlist
WHERE ticket.ticketid = ticketlist.ticketid
) > 0;
Also your database is denormalized. You are storing information in one table that can be derived from the data in another table. This redundancy can cause errors if the two ever get out of sync. I'd recommend only doing this if you need it for performance reasons.
You're better of implementing this as a view, otherwise risk the soldout number being out of sync.
CREATE VIEW vw_tickets AS
SELECT t.ticketid,
t.quantity,
COUNT(*) AS sold,
CASE
WHEN t.quantity = COUNT(*) THEN 1
WHEN t.quantity < COUNT(*) THEN -1 -- oversold
ELSE 0
END AS soldout
FROM TICKET t
LEFT JOIN TICKETLIST tl ON tl.ticketid = t.ticketid
GROUP BY t.ticketid, t.quantity
One problem I see is this:
(SELECT ticket.ticketid, COUNT(ticketlist.ticketlistid)
FROM ticket, ticketlist
WHERE ticket.ticketid = ticketlist.ticketid)
You are testing the result of that query against "> 0" however, it returns ticketid and count. You need to removed ticket.ticketid.
Try this:
UPDATE `ticket`
SET `soldout` = 1
WHERE `ticketid` IN (
SELECT `ticketid` FROM `ticketlist` GROUP BY `ticketid` HAVING COUNT(`ticketlistid`) = 2 )