I want get some of data with one distinct email.
My code is below:
SELECT DISTINCT Email,
Degree,
Majority
FROM job_education a
WHERE a.Status = 'Active'
AND a.IdEducationLevel = (
SELECT Max(b.IdEducationLevel)
FROM job_education b
WHERE b.Status='Active'
AND a.Email = b.Email
)
Thanks your kindness before
Your code should be fine, although I would fix the table aliases:
SELECT je.*
FROM job_education je
WHERE je.Status = 'Active' AND
je.IdEducationLevel = (SELECT MAX(je2.IdEducationLevel)
FROM job_education je2
WHERE je2.Status = 'Active' AND je2.Email = je.Email
);
If you are getting multiple rows for a given email -- and you want only one row -- then use a better id in the subquery:
SELECT je.*
FROM job_education je
WHERE je.Status = 'Active' AND
je.job_education_id = (SELECT je2.job_education_id
FROM job_education je2
WHERE je2.Status = 'Active' AND je2.Email = je.Email
ORDER BY IdEducationLevel DESC, job_education_id DESC
LIMIT 1
);
I have invented an id called job_education_id for this purpose. Note that this query uses ORDER BY and LIMIT rather than an aggregation function.
you should use a join
(the subselect can't see the upper reference to the table a)
SELECT DISTINCT Email,
Degree,
Majority
FROM job_education a
INNER JOIN (
SELECT b.Email, Max(b.IdEducationLevel) max_IdEducationLevel
FROM job_education b
WHERE b.Status='Active'
GROUP BY b.Email
) t ON a.Email = t.Email and a.IdEducationLevel = t.maxy_IdEducationLevel
WHERE a.Status = 'Active'
Related
I have the following select query. I want to avoid getting the duplicated "EN" row when "ES" row is present. Like prefer ES over EN.
SELECT s.soft_id,s.groupby,s.packageid,s.name,s.area,l.min,GROUP_CONCAT(DISTINCT JSON_ARRAY(s.version,s.detailid,s.filesize,s.updatetime)) versions
FROM software s
INNER JOIN langs l ON s.lang_id=l.lang_id
INNER JOIN devices_type t ON (s.familylock_id=t.familylock_id OR (s.familylock_id=0 AND s.devicelock_id=t.device_type_id))
INNER JOIN devices d ON t.device_type_id=d.device_type_id
INNER JOIN users u ON d.user_id=u.user_id
WHERE s.groupby IN(1,2,3)
AND u.token="abc"
AND d.serialno="123456789"
AND l.min IN("ES","EN")
GROUP BY s.soft_id,s.groupby,s.packageid,s.name,s.area,l.min ORDER BY s.name ASC
This is the example result. And i want to get rid of AUDI and AUTOSEARCH "EN" rows.
Image
You need to change your WHERE condition to exclude a row with l.min = 'EN' if a row with l.min = 'ES' exists. You can do this using a NOT EXISTS clause; changing the
AND l.min IN("ES","EN")
condition to
AND (l.min = 'ES' OR
l.min = 'EN' AND NOT EXISTS (SELECT *
FROM software s2
JOIN langs l2 ON l2.lang_id = s2.lang_id
WHERE s2.soft_id = s.soft_id
AND l2.min = 'ES')
)
Small sample demo on SQLFiddle
Is the below helps? I could not validate the script as I don't have sample data but below idea should help you to set the priority.
DB Fiddle
WITH preference AS
(
SELECT s.*, row_number() OVER (PARTITION BY s.soft_id
ORDER BY s.packageid,
CASE
WHEN l.min = 'ES'
THEN 'A'
ELSE 'B'
END) priority
FROM software s
INNER JOIN langs l ON s.lang_id=l.lang_id
WHERE l.min IN("ES","EN")
)
SELECT *
FROM preference
WHERE priority = 1;
I'm not sure how to make the following SQL query more efficient. Right now, the query is taking 8 - 12 seconds on a pretty fast server, but that's not close to fast enough for a Website when users are trying to load a page with this code on it. It's looking through tables with many rows, for instance the "Post" table has 717,873 rows. Basically, the query lists all Posts related to what the user is following (newest to oldest).
Is there a way to make it faster by only getting the last 20 results total based on PostTimeOrder?
Any help would be much appreciated or insight on anything that can be done to improve this situation. Thank you.
Here's the full SQL query (lots of nesting):
SELECT DISTINCT p.Id, UNIX_TIMESTAMP(p.PostCreationTime) AS PostCreationTime, p.Content AS Content, p.Bu AS Bu, p.Se AS Se, UNIX_TIMESTAMP(p.PostCreationTime) AS PostTimeOrder
FROM Post p
WHERE (p.Id IN (SELECT pc.PostId
FROM PostCreator pc
WHERE (pc.UserId IN (SELECT uf.FollowedId
FROM UserFollowing uf
WHERE uf.FollowingId = '100')
OR pc.UserId = '100')
))
OR (p.Id IN (SELECT pum.PostId
FROM PostUserMentions pum
WHERE (pum.UserId IN (SELECT uf.FollowedId
FROM UserFollowing uf
WHERE uf.FollowingId = '100')
OR pum.UserId = '100')
))
OR (p.Id IN (SELECT ssp.PostId
FROM SStreamPost ssp
WHERE (ssp.SStreamId IN (SELECT ssf.SStreamId
FROM SStreamFollowing ssf
WHERE ssf.UserId = '100'))
))
OR (p.Id IN (SELECT psm.PostId
FROM PostSMentions psm
WHERE (psm.StockId IN (SELECT sf.StockId
FROM StockFollowing sf
WHERE sf.UserId = '100' ))
))
UNION ALL
SELECT DISTINCT p.Id AS Id, UNIX_TIMESTAMP(p.PostCreationTime) AS PostCreationTime, p.Content AS Content, p.Bu AS Bu, p.Se AS Se, UNIX_TIMESTAMP(upe.PostEchoTime) AS PostTimeOrder
FROM Post p
INNER JOIN UserPostE upe
on p.Id = upe.PostId
INNER JOIN UserFollowing uf
on (upe.UserId = uf.FollowedId AND (uf.FollowingId = '100' OR upe.UserId = '100'))
ORDER BY PostTimeOrder DESC;
Changing your p.ID in (...) predicates to existence predicates with correlated subqueries may help. Also since both halves of your union all query are pulling from the Post table and possibly returning nearly identical records you might be able to combine the two into one query by left outer joining to UserPostE and adding upe.PostID is not null as an OR condition in the WHERE clause. UserFollowing will still inner join to UPE. If you want the same Post record twice once with upe.PostEchoTime and once with p.PostCreationTime as the PostTimeOrder you'll need keep the UNION ALL
SELECT
DISTINCT -- <<=- May not be needed
p.Id
, UNIX_TIMESTAMP(p.PostCreationTime) AS PostCreationTime
, p.Content AS Content
, p.Bu AS Bu
, p.Se AS Se
, UNIX_TIMESTAMP(coalesce( upe.PostEchoTime
, p.PostCreationTime)) AS PostTimeOrder
FROM Post p
LEFT JOIN UserPostE upe
INNER JOIN UserFollowing uf
on (upe.UserId = uf.FollowedId AND
(uf.FollowingId = '100' OR
upe.UserId = '100'))
on p.Id = upe.PostId
WHERE upe.PostID is not null
or exists (SELECT 1
FROM PostCreator pc
WHERE pc.PostId = p.ID
and pc.UserId = '100'
or exists (SELECT 1
FROM UserFollowing uf
WHERE uf.FollowedId = pc.UserID
and uf.FollowingId = '100')
)
OR exists (SELECT 1
FROM PostUserMentions pum
WHERE pum.PostId = p.ID
and pum.UserId = '100'
or exists (SELECT 1
FROM UserFollowing uf
WHERE uf.FollowedId = pum.UserId
and uf.FollowingId = '100')
)
OR exists (SELECT 1
FROM SStreamPost ssp
WHERE ssp.PostId = p.ID
and exists (SELECT 1
FROM SStreamFollowing ssf
WHERE ssf.SStreamId = ssp.SStreamId
and ssf.UserId = '100')
)
OR exists (SELECT 1
FROM PostSMentions psm
WHERE psm.PostId = p.ID
and exists (SELECT
FROM StockFollowing sf
WHERE sf.StockId = psm.StockId
and sf.UserId = '100' )
)
ORDER BY PostTimeOrder DESC
The from section could alternatively be rewritten to also use an existence clause with a correlated sub query:
FROM Post p
LEFT JOIN UserPostE upe
on p.Id = upe.PostId
and ( upe.UserId = '100'
or exists (select 1
from UserFollowing uf
where uf.FollwedID = upe.UserID
and uf.FollowingId = '100'))
Turn IN ( SELECT ... ) into a JOIN .. ON ... (see below)
Turn OR into UNION (see below)
Some the tables are many:many mappings? Such as SStreamFollowing? Follow the tips in http://mysql.rjweb.org/doc.php/index_cookbook_mysql#many_to_many_mapping_table
Example of IN:
SELECT ssp.PostId
FROM SStreamPost ssp
WHERE (ssp.SStreamId IN (
SELECT ssf.SStreamId
FROM SStreamFollowing ssf
WHERE ssf.UserId = '100' ))
-->
SELECT ssp.PostId
FROM SStreamPost ssp
JOIN SStreamFollowing ssf ON ssp.SStreamId = ssf.SStreamId
WHERE ssf.UserId = '100'
The big WHERE with all the INs becomes something like
JOIN ( ( SELECT pc.PostId AS id ... )
UNION ( SELECT pum.PostId ... )
UNION ( SELECT ssp.PostId ... )
UNION ( SELECT psm.PostId ... ) )
Get what you can done of that those suggestions, then come back for more advice if you still need it. And bring SHOW CREATE TABLE with you.
I have the below query to find the row prior to MAX row. i feel like i am missing something, can somebody please help with it. I ammlooking forward to get the b.usercode_1 as row prior to a.usercode_1 not the min or any other random row but the ROW prior to the MAX.
Please suggest.
Select distinct
c.ssn
, c.controlled_group_Status CG_status
, c.last_name || ' , '|| c.first_name FULL_NAME
, a.usercode_1 Current_REG
, a.eff_date effective_since1
, b.usercode_1 PRIOR_REG
, b.eff_date effective_since2
, d.term_eff_date
from employee_eff_date c
, emp_cg_data a
, emp_cg_data b
, emp_ben_elects d
where c.control_id = 'XYZ'
and c.controlled_group_Status <> 'D'
and c.eff_date = (select max( c1.eff_date)
from emp_cg_data c1
where c.control_id = c1.control_id
and c.ssn = c1.ssn)
and a.control_id = c.control_id
and a.ssn = c.ssn
and a.eff_date = (select max(a1.eff_date )
from emp_cg_data a1
where a.control_id = a1.control_id
and a.ssn = a1.ssn)
and a.usercode_1 = 'REG26'
and b.control_id = c.control_id
and b.ssn = c.ssn
and b.eff_date = (select max( b1.eff_date)
from emp_cg_data b1
where b.control_id = b1.control_id
and b.ssn = b1.ssn
and b1.eff_date < a.eff_date)
and b.usercode_1 like 'REG%'
and d.control_id = c.control_id
and d.ssn = c.ssn
and d.life_event_date = (select max( d1.life_event_date)
from emp_ben_elects d1
where d.control_id = d1.control_id
and d.ssn = d1.ssn)
and d.le_seq_no= (select max( d1.le_seq_no)
from emp_ben_elects d1
where d.control_id = d1.control_id
and d.ssn = d1.ssn
and d.life_event_date = d1.life_event_date)
and d.term_eff_date is null
;
NOTE: this is not a complete answer... its a helpful suggestion of what you should start with.
you are doing a Cartesian Product of the four tables, filtered by a WHERE... so something like this
Implicit Join -- generally not a good practice as it can be very difficult to keep the where filters apart from the join conditions.
SELECT *
FROM tableA a, TableB b
WHERE b.id = a.id
another way to write a JOIN (the more generally accepted way)
SELECT *
FROM tableA a
JOIN tableB b ON b.id = a.id
Use the ON clause to join two tables together.
You should change your joins to this format so that others can read your query and understand it better.
suggestion to solve your problem
a fairly simple way to get the second to last row is to use a row counter.
so something like
SELECT *, #row_count := #row_count + 1
FROM tableA a
JOIN tableB b on b.id = a.id AND -- any other conditions for the join.
CROSS JOIN (SELECT #row_count := 0) t
then from here you can get the MAX row, whether thats the ID or something else. and then get the #row_num -1. aka the previous row.
I currently have the following queries (and some surrounding vB code). I was hoping I could slim this up into a single SELECT statement versus having to run 10 more on each page to get that names of individuals.
$results = $db->query_read_slave("
SELECT user.id AS steam, user.skills AS level
FROM wcsp.wcgousers AS user
WHERE race = '_wcs_'
ORDER BY ABS(user.skills) DESC LIMIT 10
");
$rank = 1;
while ($user = $db->fetch_array($results)) {
$result = $db->query_first("
SELECT old.name AS name
FROM wcsp.warn_oldnames AS old
WHERE id = '$user[steam]'
ORDER BY lasttime
DESC LIMIT 1
");
$listing[] = array("id" => $user['steam'], "level" => $user['level'], "name" => $result['name'], "rank" => $rank);
$rank += 1;
}
I have tried LEFT JOIN but the issue I run into is that I would need a subquery in the LEFT JOIN similar to:
SELECT user.id AS steam, user.skills AS level, names.name AS name
FROM wcsp.wcgousers AS users
LEFT JOIN
(
SELECT names.name
FROM wcsp.warn_oldnames AS names
WHERE id = wcsp.wcgousers.id
ORDER BY lasttime DESC LIMIT 1
) AS names
ON names.id = users.id
WHERE users.race = '_wcs_'
Which won't work due to the different database check inside the subquery.
If I understand you correctly, you want to get the latest Name for every users.
SELECT a.id AS steam,
a.skills AS level,
b.name
FROM wcgousers a
INNER JOIN warn_oldnames b
ON a.ID = b.ID
INNER JOIN
(
SELECT ID, MAX(lasttime) max_date
FROM warn_oldnames
GROUP BY ID
) c ON b.ID = c.ID AND
b.lastTime = c.max_date
WHERE a.race = '_wcs_'
-- ORDER BY ABS(a.skills) DESC
-- LIMIT 10
I'm using a database that, imho, wasn't designed well, but maybe it's just me not understanding it. Anyways, I have a query that pulls the correct information, but it is really slowing down my php script. I was hoping someone could take a look at this and let me know if nesting queries to this depth is bad, and whether or not there is a way to simplify the query from the relationships depicted in the sql statement below.
SELECT name
FROM groups
WHERE id = (SELECT DISTINCT immediateparentid
FROM cachedgroupmembers
WHERE groupid = (SELECT g.id AS AdminCc
FROM Tickets t, groups g
WHERE t.Id = 124 AND t.id = g.instance AND g.type = 'AdminCc')
AND immediateparentid <> (SELECT g.id AS AdminCc
FROM Tickets t, groups g
WHERE t.Id = 124 AND t.id = g.instance AND g.type = 'AdminCc'))
Please help
Update:
Here is the output from using Explain
You may need to right click and select "View Image" for the text to be clear.
From what I can tell, you can eliminate one sub-select.
SELECT name
FROM groups
WHERE id = (
SELECT DISTINCT immediateparentid
FROM cachedgroupmembers
WHERE groupid = (
SELECT g.id
FROM Tickets t, groups g
WHERE t.Id = 124 AND t.id = g.instance AND g.type = 'AdminCc'
) AND immediateparentid != groupid
)
I'm much more used to PL/SQL on Oracle but I'll give it a try.
Get rid of aliases, you don't need them here.
Make sure columns used in the where clause are indexed (t.Id and g.type).
Don't know if MySQL indexes foreign keys by default but worth the check.
You can shorten your SQL code like that:
SELECT name
FROM groups
WHERE id = (
SELECT DISTINCT immediateparentid
FROM cachedgroupmembers
WHERE groupid = (
SELECT g.id
FROM Tickets t, groups g
WHERE t.Id = 124 AND t.id = g.instance AND g.type = 'AdminCc'
) AND immediateparentid != groupid
)
or:
SELECT name
FROM groups
WHERE id = (
SELECT DISTINCT immediateparentid
FROM cachedgroupmembers
WHERE groupid = (
SELECT g.id
FROM Tickets t inner join groups g on t.id = g.instance
WHERE t.Id = 124 AND g.type = 'AdminCc'
) AND immediateparentid != groupid
)
if your tickets table is big you may consider a temp table instead of querying it twice