Postgres SQL Query sum + count in one query - postgresql

I need help to get an result.
perscarcountoffset
person
0
1
0
1
I need a Total from a count of the lines where is person 1 + sum of the cell perscarcountoffset
select SUM((select sum(perscarcountoffset) from table where person = 1) + (select count(*) from table where person = 1)) from table where person = 1;
Thanks for any idea.
Try to create a query in postgresql. This works but it gives me 4 as result. But it must be only 2.

This returns 4 because you're actually computing
(select sum(perscarcountoffset) from table where person = 1) + (select count(*) from table where person = 1)
for each row in table (where person = 1), then summing that. So you're getting 2+2.
This is because anything outside of the aggregation method (i.e. the outer SUM() here) is per-row, and the inner sub-selects returns 2 for both rows.
The query you want doesn't need to be this complicated, this should do:
SELECT SUM(perscarcountoffset) + COUNT(*)
FROM table
WHERE person = 1;

Related

Deleting records using select statement

I am have to delete records whose count is > 1. For this, at the first step, I need to pick rec_id from custd table whose count is greater than 1 and delete data for that particular rec_id except the rec_id having highest id value.
select rec_id , field_id, count(*)
from mst.custom_data cd
group by rec_id, field_id
having count(*) > 1;
The output looks like :
rec_id field_id count
141761; 3; 2
117460; 7; 2
141970; 2; 2
select * from mst.custom_data where rec_id = '141761' and field_id=3
id field_id rec_id
200; 3; 141761
53791; 3; 141761
So, the above which is containing the least id should be deleted.
We can try using a correlated subquery here:
DELETE
FROM mst.custom_data m1
WHERE EXISTS (SELECT 1 FROM mst.custom_data m2
WHERE m1.rec_id = m2.rec_id AND m1.field_id = m2.field_id
GROUP BY rec_id, field_id
HAVING COUNT(*) > 1 AND MAX(m2.id) > m1.id);
The correlated subquery returns a record for a given (rec_id, field_id) group value if the outer id value being considered for deletion is stictly less than the max id for that group. This is the logic you requested.

Can I select a set of averages in SQL

Can I select a set of averages based on fields in SQL?
Something like:
SELECT
AVG(Salary WHERE department = 1) as AvgDept1,
AVG(Salary WHERE title = 1) as AvgTitle1,
AVG(TimeOnJob WHERE title = 1 and department = 1) as AvgTime1
FROM
Employees
I understand this is similar to AVG with a GROUP BY but I can't wrap my head around how to get the three values from this.
Those look like three separate queries,
if you want them bundled into one select you can do something like:
SELECT
(SELECT AVG(Salary) WHERE department = 1 FROM Employees) AS AvgDept1,
(SELECT AVG(Salary) WHERE title = 1 FROM Employees) AS AvgTitle1
(select AVG(TimeOnJob) WHERE title = 1 and department = 1 FROM Employees) AS AvgTime1

How to optimize selecting one random row from a set acquired by JOIN

Query in English:
Retrieve a random row from stuff.
row is not mentioned in done.
row belongs to the highest* scored friend.
*if no rows that belong to highest scored friend are found, take the next friend, an so on.
My current query takes too long to complete, because it is randomly ordering all stuff, while it should randomly order batch after batch.
Here is an sqlfiddle with tables and data.
My query:
WITH ordered_friends AS (SELECT *
FROM friends
ORDER BY score DESC)
SELECT s.stuff_id
FROM ordered_friends
INNER JOIN (SELECT *
FROM stuff
ORDER BY random()) AS s ON s.owner = ordered_friends.friend
WHERE NOT EXISTS(
SELECT 1
FROM done
WHERE done.me = 42
AND done.friend = s.owner
AND done.stuff_id = s.stuff_id
)
-- but it should keep the order of ordered_friends (score)
-- it does not have to reorder all stuff
-- one batch for each friend is enough until a satisfying row is found.
LIMIT 1;
How about this?
SELECT s.stuff_id
FROM friends
CROSS JOIN LATERAL (SELECT stuff_id
FROM stuff
WHERE stuff.owner = friends.friend
AND NOT EXISTS(SELECT 1
FROM done
WHERE done.me = 42
AND done.friend = stuff.owner
AND done.stuff_id = stuff.stuff_id
)
ORDER BY random()
LIMIT 1
) s
ORDER BY friends.score DESC
LIMIT 1;
The following indexes would make it fast:
CREATE INDEX ON friends(score); -- for sorting
CREATE INDEX ON stuff(owner); -- for the nested loop
CREATE INDEX ON done(stuff_id, friend); -- for NOT EXISTS

find rows not following by the same values in 3 columns

I have a table named raw_data with the following data
as You can see id 1 and 2 share the same values in field desa, kecamatan and kabupaten, also id 3,4,5.
So basically I want to select all rows that is not followed by the same previous values. expected result would be:
I know it's easy to do this in any programming languages such as PHP, but I need this in postgresql. is this doable? Thanks in Advance.
Assuming higher id denotes latest row, if a row with same all three columns is present not together and you don't want to filter it out as it doesn't have same values as previous row (order by id or created_date), then you can make use of analytic lag() function:
select *
from (
select
t.*,
case
when desa = lag(desa) over (order by id)
and kecamatan = lag(kecamatan) over (order by id)
and kabupaten = lag(kabupaten) over (order by id)
then 0 else 1
end flag
from your_table t
) t where flag = 1;

Summing From Consecutive Rows

Assume we have a table and we want to do a sum of the Expend column so that the summation only adds up values of the same Week_Name.
SN Week_Name Exp Sum
-- --------- --- ---
1 Week 1 10 0
2 Week 1 20 0
3 Week 1 30 60
4 Week 2 40 0
5 Week 2 50 90
6 Week 3 10 0
I will assume we will need to `Order By' Week_Name, then compare the previous Week_Name(previous row) with the current row Week_name(Current row).
If both are the same, put zero in the SUM column.
If not the same, add all expenditure, where Week_Name = Week_Name(Previous row) and place in the Sum column. The final output should look like the table above.
Any help on how to achieve this in T-SQL is highly appreciated.
Okay, I was eventually able to resolve this issue, praise Jesus! If you want the exact table I gave above, you can use GilM's response below, it is perfect. If you want your table to have running Cumulatives, i.e. Rows 3 shoud have 60, Row 5, should have 150, Row 6 160 etc. Then, you can use my code below:
USE CAPdb
IF OBJECT_ID ('dbo.[tablebp]') IS NOT NULL
DROP TABLE [tablebp]
GO
CREATE TABLE [tablebp] (
tablebpcCol1 int PRIMARY KEY
,tabledatekey datetime
,tableweekname varchar(50)
,expenditure1 numeric
,expenditure_Cummulative numeric
)
INSERT INTO [tablebp](tablebpcCol1,tabledatekey,tableweekname,expenditure1,expenditure_Cummulative)
SELECT b.s_tablekey,d.PK_Date,d.Week_Name,
SUM(b.s_expenditure1) AS s_expenditure1,
SUM(b.s_expenditure1) + COALESCE((SELECT SUM(s_expenditure1)
FROM source_table bs JOIN dbo.Time dd ON bs.[DATE Key] = dd.[PK_Date]
WHERE dd.PK_Date < d.PK_Date),0)
FROM source_table b
INNER JOIN dbo.Time d ON b.[Date key] = d.PK_Date
GROUP BY d.[PK_Date],d.Week_Name,b.s_tablekey,b.s_expenditure1
ORDER BY d.[PK_Date]
;WITH CTE AS (
SELECT tableweekname
,Max(expenditure_Cummulative) AS Week_expenditure_Cummulative
,MAX(tablebpcCol1) AS MaxSN
FROM [tablebp]
GROUP BY tableweekname
)
SELECT [tablebp].*
,CASE WHEN [tablebp].tablebpcCol1 = CTE.MaxSN THEN Week_expenditure_Cummulative
ELSE 0 END AS [RunWeeklySum]
FROM [tablebp]
JOIN CTE on CTE.tableweekname = [tablebp].tableweekname
I'm not sure why your SN=6 line is 0 rather than 10. Do you really not want the sum for the last Week? If having the last week total is okay, then you might want something like:
;WITH CTE AS (
SELECT Week_Name,SUM([Expend.]) as SumExpend
,MAX(SN) AS MaxSN
FROM T
GROUP BY Week_Name
)
SELECT T.*,CASE WHEN T.SN = CTE.MaxSN THEN SumExpend
ELSE 0 END AS [Sum]
FROM T
JOIN CTE on CTE.Week_Name = T.Week_Name
Based on the requst in the comment wanting a running total in SUM you could try this:
;WITH CTE AS (
SELECT Week_Name, MAX(SN) AS MaxSN
FROM T
GROUP BY Week_Name
)
SELECT T.SN, T.Week_Name,T.Exp,
CASE WHEN T.SN = CTE.MaxSN THEN
(SELECT SUM(EXP) FROM T T2
WHERE T2.SN <= T.SN) ELSE 0 END AS [SUM]
FROM T
JOIN CTE ON CTE.Week_Name = T.Week_Name
ORDER BY SN