I have (for me at least) a complex query that I build with examples from this site. The last thing I added was the IF statement. Without the IF statement it was working with the TRUE part of the IF statement. I hope you girls/guys can help me out here. This is the query :
SELECT
t.ID, t.start_time, t.end_time, t.start_date, t.end_date, t.balance,
u1.first_name AS teacher_one_first_name, u1.last_name AS teacher_one_last_name,
u2.first_name AS teacher_two_first_name, u2.last_name AS teacher_two_last_name,
company.name, company.post_city, tag, lvl,
IF(
t.balance=1,
(
(SELECT count(user_ID)
FROM company_lesson_block_student
WHERE lead_follow=0 AND company_lesson_block_ID=t.ID) AS lead,
(SELECT count(user_ID)
FROM company_lesson_block_student
WHERE lead_follow=1 AND company_lesson_block_ID=t.ID) AS follow
),
(SELECT count(user_ID)
FROM company_lesson_block_student
WHERE company_lesson_block_ID=t.ID) AS total_student
)
FROM company_lesson_block AS t
LEFT JOIN company_lvl ON company_lvl.ID = t.lvl_ID
LEFT JOIN tag ON tag.ID = t.style_ID
LEFT JOIN company ON company.ID=t.location_ID
LEFT JOIN user AS u1 ON t.teacher_one_ID=u1.ID
LEFT JOIN user AS u2 ON t.teacher_two_ID=u2.ID
WHERE t.company_ID='1' AND location_ID='1' AND company_season_ID='1'
ORDER BY start_date ASC
The error message i get is:
You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version
for the right syntax to use near 'AS lead, (SELECT count(user_ID) FROM company_less' at line 10
Any help/tips are appriciated
You want to return 2 columns, but IF can return only 1, so you need 2 IFs:
........................
IF(
t.balance=1,
(SELECT count(user_ID)
FROM company_lesson_block_student
WHERE lead_follow=0 AND company_lesson_block_ID=t.ID),
(SELECT count(user_ID)
FROM company_lesson_block_student
WHERE company_lesson_block_ID=t.ID)
) AS ????,
IF(
t.balance=1,
(SELECT count(user_ID)
FROM company_lesson_block_student
WHERE lead_follow=1 AND company_lesson_block_ID=t.ID),
(SELECT count(user_ID)
FROM company_lesson_block_student
WHERE company_lesson_block_ID=t.ID)
) AS ????
........................
You must set the aliases after the closing parenthesis of IF.
Maybe you must rethink this logic because in case of FALSE, the same value is returned twice.
Related
I want to use data of view in WHERE clause. But getting an error:
create view post_with_answers AS
SELECT DISTINCT postid
FROM (SELECT postid FROM `qa_posts` WHERE `type` = 'Q') AS q1
INNER JOIN (SELECT parentid FROM `qa_posts` WHERE `type` = 'A') AS q2 ON q1.postid = q2.parentid
select count(*)
from qa_posts
where parentid not in post_with_answers
On the last row I am getting this error:
SQL Error [1064] [42000]: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'post_with_answers' at line 3
How to fix that?
Just like you would use a table:
select count(*)
from qa_posts
where parentid not in (select pwa.postid from post_with_answers pwa);
I would caution you from using not in with a subquery. No rows are returned if even one value from the subquery is NULL. For this reason, I recommend NOT EXISTS:
select count(*)
from qa_posts p
where not exists (select 1
from post_with_answers pwa
where p.parentid = pwa.postid
);
In addition, your view definition is a bit over complicated. You don't need subqueries:
create view post_with_answers AS
SELECT DISTINCT pq.postid
FROM qa_posts pq JOIN
qa_posts pa
ON pq.postid = pa.parentid
WHERE pq.type = 'Q' AND pa.type = 'A';
Then, the DISTINCT just adds overhead, so EXISTS is better:
create view post_with_answers AS
SELECT DISTINCT pq.postid
FROM qa_posts pq
WHERE EXISTS (SELECT 1
FROM qa_posts pa
WHERE pq.postid = pa.parentid AND
pa.type = 'A'
)
WHERE pq.type = 'Q';
I have the following tables:
Task (id,....)
TaskPlan (id, task_id,.......,end_at)
Note that end_at is a timestamp and that one Task has many TaskPlans. I need to query for the MAX end_at for each Task.
This query works fine, except when you have the same exact timestamp for different TaskPlans. In that case, I would be returned multiple TaskPlans with the MAX end_at for the same Task.
I know this is an unlikely situation, but is there anyway I can limit the number of results for each task_id to 1?
My current code is:
SELECT * FROM Task AS t
INNER JOIN (
SELECT * FROM TaskPlan WHERE end_at in (SELECT MAX(end_at) FROM TaskPlan GROUP BY task_id )
) AS pt
ON pt.task_id = t.id
WHERE status = 'plan';
This works, except in the above situation, how can this be achieved?
Also in the subquery, instad of SELECT MAX(end_at) FROM TaskPlan GROUP BY task_id, is it possible to do something like this so I can use TaskPlan.id for the where in clause?
SELECT id, MAX(end_at) FROM TaskPlan GROUP BY task_id
When I try, it gives the following error:
SQL Error [1055] [42000]: Expression #1 of SELECT list is not in GROUP
BY clause and contains nonaggregated column 'TaskPlan.id' which is not
functionally dependent on columns in GROUP BY clause; this is
incompatible with sql_mode=only_full_group_by
Any explaination and suggestion would be much welcome!
Note on duplicate label: (Now reopened)
I already studied the this question, but it does not provide an answer for my situation where there are multiple max values in the result and it needs to be filtered out to include only one result row per group.
Use the id rather than the timestamp:
SELECT *
FROM Task AS t INNER JOIN
(SELECT tp.*
FROM TaskPlan tp
WHERE tp.id = (SELECT tp2.id FROM TaskPlan tp2 WHERE tp2.task_id = tp.task_id ORDER BY tp2.end_at DESC LIMIT 1)
) tp
ON tp.task_id = t.id
WHERE status = 'plan';
Or use in with tuples:
SELECT *
FROM Task AS t INNER JOIN
(SELECT tp.*
FROM TaskPlan tp
WHERE (tp.task_id, tp.end_at) in (SELECT tp2.task_id, MAX(tp2.end_at)
FROM TaskPlan tp2
GROUP BY tp2.task_id
)
) tp
ON tp.task_id = t.id
WHERE status = 'plan';
If you want to get a list of task ID's with MAX end_at for each, run the query below:
SELECT t.id, MAX(tp.end_at) FROM Task t JOIN TaskPlan tp on t.id = tp.task_id GROUP BY t.id;
EDIT:
Now, I know what exactly you are going to do.
If the TaskPlan table is so big, you can avoid the 'GROUP BY' and run the query below that is very efficient:
SET #first_row := 0;
SET #task_id := 0;
SELECT * FROM Task t JOIN (
SELECT tp.*
, IF(#task_id = tp.`task_id`, #first_row := 0, #first_row := 1) AS temp
, #first_row AS latest_record
, #task_id := tp.`task_id`
FROM TaskPlan tp ORDER BY task_id, end_at DESC) a ON t.task_id = a.task_id AND a.latest_record = 1;
Try this query:
select t.ID , tp1.end_at
from TASK t
left join TASKPLAN tp1 on t.ID = tp1.id
left join TASKPLAN tp2 on t.ID = tp2.id and tp1.end_at < tp2.end_at
where tp2.end_at is null;
I am trying to SELECT from one table and count from two other tables based on the rows from the first table. I tried the following code below but the rows keep coming empty.
SELECT list.id, list.title, list.body, list.poster, list.created_at, count(comments.id) as comcount, count(supports.topic_id) as supcount
FROM (
SELECT *
FROM topics
ORDER BY created_at DESC
LIMIT 5
) AS list, comments, supports
WHERE
list.id = comments.id OR
list.id = supports.topic_id
Through in this scenario table topics has only two rows and tables comments and supports have no rows in them, but yet still I should be able to get two rows with their aliases supcount and comcount each having a value 0 as an output.
I got the solution to the above but am trying something else with the solution provided which I explained in the comment area of the solution provided.
SELECT
t.id,
t.title,
t.body,
t.poster,
t.created_at,
s.supporter,
IFNULL((SELECT COUNT(*) FROM comments c WHERE c.id = t.id), 0) AS comcount,
IFNULL((SELECT COUNT(*) FROM supports s WHERE s.topic_id = t.id), 0) AS supcount,
CASE WHEN (s.supporter = "Davies Alex") THEN '1' ELSE '0' END sup,
CASE WHEN (c.commenter = "Davies Alex") THEN '1' ELSE '0' END com
FROM topics t, comments c, supports s
ORDER BY created_at DESC
This gonna be working, give a try (using subquery for just counting entries in another table is more suitable):
SELECT
id,
title,
body,
poster,
created_at,
IFNULL((SELECT COUNT(*) FROM comments c WHERE c.id = t.id), 0) AS comcount,
IFNULL((SELECT COUNT(*) FROM supports s WHERE s.topic_id = t.id), 0) AS supcount
FROM topics t
ORDER BY created_at DESC
LIMIT 5
Update for new requirement:
SELECT
t.id,
t.title,
t.body,
t.poster,
t.created_at,
s.supporter,
IFNULL(COUNT(c.id), 0) AS comcount,
IFNULL(COUNT(s.id), 0) AS supcount,
SUM(IF(s.supporter IS NOT NULL AND s.supporter = "Davies Alex", 1, 0)) > 0 AS sup,
SUM(IF(c.commenter IS NOT NULL AND c.commenter = "Davies Alex", 1, 0)) > 0 AS com
FROM topics t
LEFT JOIN comments c ON c.id = t.id
LEFT JOIN supports s ON s.topic_id = t.id
GROUP BY t.id
ORDER BY created_at DESC
In your query, you require list.id to either match comments.id or supports.topic_id. If you use an outer join, you'll be able to retrieve data from the initial table even though the joined tables don't match or contain any data.
SELECT
topics.id, topics.title, topics.body, topics.poster, list.created_at,
count(comments.id) as comcount,
count(supports.topic_id) as supcount
FROM lists
LEFT JOIN comments ON comments.id = topics.id
LEFT JOIN supports ON supports.topic_id = topics.id
ORDER BY created_at DESC
LIMIT 5
I am trying to bring back a string based on an IF statement but it is extremely slow.
It has something to do with the first subquery but I am unsure of how to rearrange this as to bring back the same results but faster.
Here is my SQL:
SELECT IF
(
(
SELECT COUNT(*)
FROM
(
SELECT DISTINCT enquiryId, type
FROM parts_enquiries, parts_service_types AS pst
WHERE parts_enquiries.serviceTypeId = pst.id
) AS parts
WHERE parts.enquiryId = enquiries.id
) > 1, 'Mixed',
(
SELECT DISTINCT type
FROM parts_enquiries, parts_service_types AS pst
WHERE parts_enquiries.serviceTypeId = pst.id AND enquiryId = enquiries.id
)
) AS partTypes
FROM enquiries,
entities
WHERE enquiries.entityId = entities.id
How can I make it faster?
I have modified my original query below, but I am getting the error that subquery returns more than one row:
SELECT
(SELECT
CASE WHEN COUNT(DISTINCT type) > 1 THEN 'Mixed' ELSE `type` END AS type
FROM parts_enquiries
INNER JOIN parts_service_types AS pst ON parts_enquiries.serviceTypeId = pst.id
INNER JOIN enquiries ON parts_enquiries.enquiryId = enquiries.id
INNER JOIN entities ON enquiries.entityId = entities.id
GROUP BY enquiryId) AS partTypes
FROM enquiries,
entities
WHERE enquiries.entityId = entities.id
Please have a look if this query yields the same results:
SELECT
enquiryId,
CASE WHEN COUNT(DISTINCT type) > 1 THEN 'Mixed' ELSE `type` END AS type
FROM parts_enquiries
INNER JOIN parts_service_types AS pst ON parts_enquiries.serviceTypeId = pst.id
INNER JOIN enquiries ON parts_enquiries.enquiryId = enquiries.id
INNER JOIN entities ON enquiries.entityId = entities.id
GROUP BY enquiryId
But N.B.'s comment is still valid. To see if and index is used and other information we need to see the EXPLAIN and the table definitions.
This should get you what you want.
I would first pre-query your parts enquiries and parts service types looking for both the count and MINIMUM of the part 'type', grouped by the enquiry ID.
then, run your IF() against that result. If the distinct count is > 0, then 'Mixed'. If only one, since I did the MIN(), it would only have the description of that one value that you desire anyhow.
SELECT
E.ID
IF ( PreQuery.DistTypes > 1, 'Mixed', PreQuery.FirstType ) as PartType
from
Enquiries E
JOIN ( SELECT
PE.EnquiryID,
COUNT( DISTINCT PE.ServiceTypeID ) as DistTypes,
MIN( PST.Type ) as FirstType
from
Parts_Enquiries PE
JOIN Parts_Service_Types PST
ON PE.ServiceTypeID = PST.ID
group by
PE.EnquiryID ) as PreQuery
ON E.ID = PreQuery.EnquiryID
How do I put these two queries into a single query?
select count(id) as cnt from {$site_id}.proofingv2_packages where active='1'
select count(id) as cnt from {$site_id}.proofingv2_package_options where active='1' and parent={$row["id"]} order by sort
$row['id'] is the id field from the first query. I am trying to determine if there are any valid packages. A valid package must be active and have at least 1 active option. Running 2 queries for this doesn't seem right.
Can anyone help?
select count(id) as cnt from
{$site_id}.proofingv2_packages pp
INNER JOIN
{$site_id}.proofingv2_package_options
pt ON pp.active = pt.Active AND
pp.Active = 1
if the id is the PK or FK on the same on both tables use this query
select count(id) as cnt from
{$site_id}.proofingv2_packages pp
INNER JOIN {$site_id}.proofingv2_package_options pt ON pp.id= pt.id
AND pp.Active = 1
SELECT IF(count(*) > 0, 1, 0) AS isValid
FROM {$site_id}.proofingv2_packages pp
INNER JOIN {$site_id}.proofingv2_package_options ppo ON ppo.parent = pp.id
WHERE pp.active = '1'
AND ppo.active = '1'
This should return 1 if there are valid packages or 0 if not