Hi i have table1 and table2.
table1 is the logtime table of employees and table2 is the groupcode of the employee.
On table1 some employees has duplicate time in because they time in multiple time to just to secure their time in.
Table1
ID EMPID Time_IN
1 001 7:01 AM
2 004 7:04 AM
3 034 7:10 AM
4 034 7:11 AM
5 019 7:11 AM
6 019 7:12 AM
Table2
ID empID GroupName
1 001 AA
2 004 AB
3 034 AA
4 019 AA
result
GroupName CNT
AA 5
AB 1
Expected result
GroupName CNT
AA 3
AB 1
current query
Select b.GroupName, count(*) as cnt
from table1 a
inner join table2 b
on a.EMPID = b.empID
Group by b.GroupName
How can i achive as expected result above?
Thankyou in advance.
you can use distinct count as follows:
select t2.groupname, count(distinct empid) as cnt
from table1 t1 join table2 t2
on t1.empid = t2.empid
group by t2.groupname
The join is superfluous for the question you have asked:
select t2.GroupName, count(*) as cnt
from table2 t2
group by t2.GroupName;
This is much more efficient than joining and using count(distinct). You probably really have a different question, which should be asked as a new question.
Related
I have 3 tables Trial1, TrialMid and Trial2. The tables are as follows :
Trial1:
ID Location Numbers
--------------------------
TR1 US 890
TR2 AME 876
TR3 HUY 78
TrialMid
ID Trial2Id Area Trial1id
----------------------------------------
TRM01 tr11 45 TR1
TRM02 tr11 345 TR1
TRM03 tr22 456 TR1
Trial2
ID Name Area Reference
-----------------------------------------
tr11 Guza 897 324
tr22 asd 876 12
These are the three tables and I want to get the ID from Trial2 using the Id from Trial1.
I want this output (using the Trial1id):
ID
-----
tr11
tr22
I also want to get the count of the Trial2 Ids but I can't use "group by".
The challenge I am facing is that the query that I want is to get the result as :
Total Trial1
----------------
2 TR1
Id Trial1
-----------------
tr11 TR1
tr22 TR1
I want to get the Ids from the table Trial2 and not from TrialMid. If I use count() by using group by it is giving me result as
Total Trial1
-----------------
2 TR1
1 TR1
Your question is very hard to follow. But I think you might be asking for the number of distinct Trial2Ids in the "mid" table for each Trialid. If so:
select trial1id, count(distinct Trial2Id )
from TrialMid
group by trial1id;
You can try the below -
select trial1id,count(*) as total
from
(
select t.id as trial2id,t1.id as trial1id,row_number() over(partition by tm.Trial2Id order by tm.Area desc) as rn
from Trial2 t inner join TrialMid tm on t.id=tm.Trial2Id
inner join Trial1 t1 on tm.Trial1id=t1.id
)A where rn=1
As far as I can understand you're looking for a window function including PARTITION BY clause as mentioning that you can't use "group by" :
SELECT DISTINCT T2.ID AS "Total",
COUNT(T2.ID) OVER (PARTITION BY T1.ID, T2.ID) AS "Trial1"
FROM TrialMid TM
JOIN Trial2 T2
ON T2.ID = TM.Trial2Id
JOIN Trial1 T1
ON T1.ID = TM.Trial1Id
Total Trial1
tr11 2
tr22 1
Demo
I'm trying to lookup a unique value from table b and get it into table a.
Table b stores multiple values that are changing by date.
I would like to join but only getting the values with the latest date from table b.
Table a
Unique ID
1
2
Table b
Date Unique ID Price
01/01/2019 1 100
01/02/2019 1 101
01/03/2019 1 102
01/01/2019 2 90
01/02/2019 2 91
01/03/2019 2 92
Expected result
Unique ID Price Date
1 102 01/03/2019
2 92 01/03/2019
Appreciate your help!
Have a sub-query that returns each UniqueID together with its max date. IN that result.
select * from tablename
where (UniqueID, date) in (select UniqueID, max(date)
from tablename
group by UniqueID)
You want correlated subquery :
select b.*
from tableb b
where b.date = (select max(b1.date) from tableb b1 where b1.UniqueID = b.UniqueID);
If you want to go with JOIN then you can do JOIN with subquery :
select a.UniqueID , b.Price, b.Date
from tablea a inner join
tableb b
on b.UniqueID = a.UniqueID
where b.date = (select max(b1.date) from tableb b1 where b1.UniqueID = a.UniqueID);
A correlated subquery?
select b.*
from b
where b.date = (select max(b2.date) from b b2 where b2.unique_id = b.unique_id);
I am having a few issues making a MAX function work within the select statement See example data below:
Table 1 Table 2
Visit_ID Car_ID Move_ID Visit_ID MoveStartDate MoveEndDate
A 1 1 A 25/07/2016 27/07/2016
B 2 2 A 28/07/2016 28/07/2016
C 1 3 B 19/07/2016 22/07/2016
D 3 4 D 28/06/2016 30/06/2016
I would like my select statement to pick the min start time and Max start time based on the Visit_ID so I would be expecting:
Result
Visit_ID Car_ID StartDate EndDate
A 1 25/07/2016 28/07/2016
B 2 19/07/2016 22/07/2016
So far I have tried I already have Inner Joins in my select statement:
,(MAX (EndDate) WHERE Visit.Visit_ID = Move.Visit_ID) AS End Date
I have looked at some other queries with a second select statement within the select so you end up with something like:
Select Visit_ID, Car_ID ,(Select MAX(EndDate) FULL OUTER JOIN Table 2 ON Table 1.Visit_ID = Table 2.Visit_ID Group By Table 1.Visit_ID) AS End Date
Hope I have provided enough info currently stumped.
If you also want Car_ID = 3 in the result:
select t1.Visit_ID, t1.Car_ID, MIN(MoveStartDate), MAX(MoveEndDate)
from table1 t1
join table2 t2 on t1.Visit_ID = t2.Visit_ID
group by t1.Visit_ID, t1.Car_ID
Returns:
SQL>select t1.Visit_ID, t1.Car_ID, MIN(MoveStartDate), MAX(MoveEndDate)
SQL&from table1 t1
SQL& join table2 t2 on t1.Visit_ID = t2.Visit_ID
SQL&group by t1.Visit_ID, t1.Car_ID;
visit_id car_id
======== =========== ==================== ====================
A 1 25/07/2016 28/07/2016
B 2 19/07/2016 22/07/2016
D 3 28/06/2016 30/06/2016
3 rows found
I did not check it but your can try this
WITH cte
AS
(select Move_ID,Visit_ID,min(MoveStartDate) AS mMS,MAX(MoveEndDate) AS mME
FROM Table_2
GROUP BY Move_ID,Visit_ID)
SELECT c.Move_ID,c.Visit_ID,T1.Car_ID,c.mMS,c.mME
FROM Table_1 as T1 JOIN cte as C
ON c.Visit_ID=T1.Visit_ID
I have a three tables
Table 1
Id Department
1 A
2 B
3 C
4 D
Table 2
Id DepartId Name
1 1 ABC
2 1 DEF
3 1 ASD
4 2 FGH
5 2 HJK
6 3 ZXC
Table 3
Id Depart Area
1 A pp
2 B
3 C nn
4 D oo
I need the result
Id Depart Name Area
1 A ABC pp
2 B FGH Null
3 C ZXC nn
4 D NULL oo
I need one matching entry from table 2 and table 3 to corresponding entry in the table 1
Do a left join to also get t1 rows without any reference in the t2 table. GROUP BY to get only 1 row per Department.
select t1.id, t1.Department, min(t2.Name)
from t1
left join t2 on t1.id = t2.DepartId
group by t1.id, t1.Department
I think I would do this with a correlated subquery:
select t1.*,
(select t2.name
from t2
where t1.id = t2.DepartId and rownum = 1
) as t2name
from t1;
This saves the overhead of an aggregation. An index on t2(DepartId, name) is optimal for this query.
by the way not the answer to your specific question but if instead of just one you want all the names you can use listagg
SELECT t1.id,
department,
LISTAGG (name, ',') WITHIN GROUP (ORDER BY name) names
FROM t1, t2
WHERE t1.id = t2.departId(+)
GROUP BY t1.id, department
ORDER BY 1
ID Department Names
1 A ABC,ASD,DEF
2 B FGH, HJK
3 C ZXC
4 D
I have one complicated question. I'll try to explain it with example:
have one table that have primary key, and I want to join other table there the first's table primary key is foreign key, and I want If in the second table there is duplicate foreign key to select the number of repeatability. For example:
1-st table:
id name
--- -----
1 Greg
2 Alan
3 George
4 John
5 Peter
2-nd table
id aid data
--- ----- -------
1 2 CCCV
2 2 VVVV
3 3 DDDDD
4 3 SSSS
5 4 PPPPP
I want the result of the join to be:
id(1st table) aid name Data Number
----------- ---- ----- ----- -----
1 null Greg null 1
2 1 Alan CCCV 1
2 2 Alan VVVV 2
3 3 George DDDDD 1
3 4 George SSSS 2
4 5 John PPPPP 1
5 null Peter null 1
I searched a lot, I couldn't find anything. Maybe I do not know how search, or there is no such thing as what I want to do.
SELECT Table1.id, Table2.id as aid, Table1.name, Table2.data,
GREATEST(1, (SELECT COUNT(*)
FROM Table2 t2
WHERE t2.aid = Table1.id
AND t2.id <= Table2.id))
AS number
FROM Table1
LEFT JOIN Table2
ON Table2.aid = Table1.id
ORDER BY id, aid;
works in both MySQL and PostgreSQL.
As per my comment, you've tagged this both MySQL and PostgreSQL.
This answer is for PostgreSQL.
SELECT
table1.id,
table2.aid,
table1.name,
table2.data,
ROW_NUMBER() OVER (PARTITION BY table1.id ORDER BY table2.aid) AS number
FROM
table1
LEFT JOIN
table2
ON table1.id = table2.aid
Queries for PostgreSQL 8.3 which has no window functions.
With bigger tables it is regularly much faster to use a JOIN instead of a correlated sub-query.
The first query aggregates values for Table2 before joining to Table1, which should befaster, too:
SELECT t1.id, t2.aid, t1.name, t2.data, COALESCE(t2.ct, 1) AS number
FROM Table1 t1
LEFT JOIN (
SELECT x.aid, x.data, count(y.aid) + 1 AS ct
FROM Table2 x
LEFT JOIN Table2 y ON x.aid = y.aid AND x.id > y.id
GROUP BY x.aid, x.data
) t2 ON t2.aid = t1.id
ORDER BY t1.id, t2.ct;
And ORDER BY should be fixed.
Alternative without sub-query. Might be faster, yet:
SELECT t1.id, t2.aid, t1.name, t2.data, count(*) + count(t3.id) AS number
FROM Table1 t1
LEFT JOIN Table2 t2 ON t2.aid = t1.id
LEFT JOIN Table2 t3 ON t3.aid = t2.aid AND t3.id < t2.id
GROUP BY t1.id, t2.aid, t1.name, t2.data
ORDER BY t1.id, count(t3.id);
Not sure, didn't test with a bigger set. Test performance with EXPLAIN ANALYZE. Could you report back your results?