If I query:
select max(date_created) date_created
on a datefield in PL/SQL (Oracle 11g), and there are records that were created on the same date but at different times, Max() returns only the latest times on that date. What I would like to do is have the times be ignored and return ALL records that match the max date, regardless of their associated timestamp in that column. What is the best practice for doing this?
Edit: what I'm looking to do is return all records for the most recent date that matches my criteria, regardless of varying timestamps for that day. Below is what I'm doing now and it only returns records from the latest date AND time on that date.
SELECT r."ID",
r."DATE_CREATED"
FROM schema.survey_response r
JOIN
(SELECT S.CUSTOMERID ,
MAX (S.DATE_CREATED) date_created
FROM schema.SURVEY_RESPONSE s
WHERE S.CATEGORY IN ('Yellow', 'Blue','Green')
GROUP BY CUSTOMERID
) recs
ON R.CUSTOMERID = recs.CUSTOMERID
AND R.DATE_CREATED = recs.date_created
WHERE R.CATEGORY IN ('Yellow', 'Blue','Green')
Final Edit: Got it working via the query below.
SELECT r."ID",
r."DATE_CREATED"
FROM schema.survey_response r
JOIN
(SELECT S.CUSTOMERID ,
MAX (trunc(S.DATE_CREATED)) date_created
FROM schema.SURVEY_RESPONSE s
WHERE S.CATEGORY IN ('Yellow', 'Blue','Green')
GROUP BY CUSTOMERID
) recs
ON R.CUSTOMERID = recs.CUSTOMERID
AND trunc(R.DATE_CREATED) = recs.date_created
WHERE R.CATEGORY IN ('Yellow', 'Blue','Green')
In Oracle, you can get the latest date ignoring the time
SELECT max( trunc( date_created ) ) date_created
FROM your_table
You can get all rows that have the latest date ignoring the time in a couple of ways. Using analytic functions (preferrable)
SELECT *
FROM (SELECT a.*,
rank() over (order by trunc(date_created) desc) rnk
FROM your_table a)
WHERE rnk = 1
or the more conventional but less efficient
SELECT *
FROM your_table
WHERE trunc(date_created) = (SELECT max( trunc(date_created) )
FROM your_table)
Related
It is actually possible to use # (the at sign) with sqlite to be able to use a calculated value as a constant in an other query ?
I am using a variable(a total) that i calculated previously to get an other variable (a proportion) over two time periods.
Total amout of sale
Proportion of sale between the first semester and second semester.
I copy the first query to get the constant and i had the first query to the second.
The answer is no BUT:-
This could possibly be done in a single query.
Consider this simple demo with hopefully easy to understand all-in-one queries:-
First the sales table:-
i.e. 2 columns semester and amount
10 rows in total so 1000 is the total amount
6 rows are S1 (amount is 600) so 60%
4 rows are S2 (amount is 400) so 40%
Created and populated using:-
CREATE TABLE IF NOT EXISTS sales (semester TEXT, amount REAL);
INSERT INTO sales VALUES('S1',100),('S1',100),('S1',100),('S1',100),('S1',100),('S1',100),('S2',100),('S2',100),('S2',100),('S2',100);
So you could use an all-in-one query such as:-
SELECT
(SELECT sum(amount) FROM sales) AS total,
(SELECT sum(amount) FROM sales WHERE semester = 'S1') AS s1total,
((SELECT sum(amount) FROM sales WHERE semester = 'S1') / (SELECT sum(amount) FROM sales)) * 100 AS s1prop,
(SELECT sum(amount) FROM sales WHERE semester = 'S2') AS s2total,
((SELECT sum(amount) FROM sales WHERE semester = 'S2') / (SELECT sum(amount) FROM sales)) * 100 AS s2prop
;
This would result in
i.e. s1prop and s2prop the expected results (the other columns may be useful)
An alternative, using a CTE (Common Table Expressions) that does the same could be:-
WITH cte_total(total,s1total,s2total) AS (SELECT
(SELECT sum(amount) FROM sales),
(SELECT sum(amount) FROM sales WHERE semester = 'S1'),
(SELECT sum(amount) FROM sales WHERE semester = 'S2')
)
SELECT total, s1total, (s1total / total) * 100 AS s1prop, s2total, (s2total / total) * 100 AS s2prop FROM cte_total;
you can have multiple CTE's and gather data from other tables or even being passed as parameters. They can be extremely useful and would even allow values to be accessed throughout.
e.g.
Here's an example where a 2nd cte is added (as the first cte) that mimics passing 3 dates (instead of the hard coded values ?'s could be coded and the parameters passed via parameter binding).
As the sales table has no date for the sale a literal value has been coded, this would be normally be the column with the sale date instead of WHERE '2023-01-01' /*<<<<< would be the column that holds the date */
the hard coded date has purposefully been used so result in the BETWEEN clause resulting in true.
if the date column did exist then WHERE criteria for the semester could then be by between the respective dates for the semester.
The example:-
WITH
dates AS (SELECT
'2023-01-01' /*<<<<< ? and can then be passed as bound parameter*/ AS startdate,
'2023-03-01' /*<<<<< ? and can then be passed as bound parameter*/ AS semester2_start,
'2023-05-30' /*<<<<< ? and can then be passed as bound parameter*/as enddate
),
cte_total(total,s1total,s2total) AS (SELECT
(SELECT sum(amount) FROM sales
WHERE '2023-01-01' /*<<<<< would be the column that holds the date */
BETWEEN (SELECT startdate FROM dates)
AND (SELECT enddate FROM dates)),
(SELECT sum(amount) FROM sales WHERE semester = 'S1'),
(SELECT sum(amount) FROM sales WHERE semester = 'S2')
)
SELECT total, s1total, (s1total / total) * 100 AS s1prop, s2total, (s2total / total) * 100 AS s2prop FROM cte_total;
My database structure contains columns: id, name, value, dealer. I want to retrieve row with lowest value for each dealer. I've been trying to mess up with MIN() and GROUP BY, still - no solution.
Solution1:
SELECT t1.* FROM your_table t1
JOIN (
SELECT MIN(value) AS min_value, dealer
FROM your_table
GROUP BY dealer
) AS t2 ON t1.dealer = t2.dealer AND t1.value = t2.min_value
Solution2 (recommended, much faster than solution1):
SELECT t1.* FROM your_table t1
LEFT JOIN your_table t2
ON t1.dealer = t2.dealer AND t1.value > t2.value
WHERE t2.value IS NULL
This problem is very famous, so there is a special page for this in Mysql's manual.
Check this: Rows Holding the Group-wise Maximum/Minimum of a Certain Column
select id,name,MIN(value) as pkvalue,dealer from TABLENAME
group by id,name,dealer;
here you group all rows by id,name,dealer and then you will get min value as pkvalue.
SELECT MIN(value),dealer FROM table_name GROUP BY dealer;
First you need to resolve the lowest value for each dealer, and then retrieve rows having that value for a particular dealer. I would do this that way:
SELECT a.*
FROM your_table AS a
JOIN (SELECT dealer,
Min(value) AS m
FROM your_table
GROUP BY dealer) AS b
ON ( a.dealer= b.dealer
AND a.value = b.m )
Try following:
SELECT dealer, MIN(value) as "Lowest value"
FROM value
GROUP BY dealer;
select id, name, value, dealer from yourtable where dealer
in(select min(dealer) from yourtable group by name, value)
These answers seem to miss the edge case of having multiple minimum values for a dealer and only wanting to return one row.
If you want to only want one value for each dealer you can use row_number partition - group - the table by dealer then order the data by value and id. we have to make the assumption that you will want the row with the smallest id.
SELECT ord_tbl.id,
ord_tbl.name,
ord_tbl.value,
ord_tbl.dealer
FROM (SELECT your_table.*,
ROW_NUMBER() over (PARTITION BY dealer ORDER BY value ASC, ID ASC)
FROM your_table
) AS ord_tbl
WHERE ord_tbl.ROW_NUMBER = 1;
Be careful though that value, id and dealer are indexed. If not this will do a full table scan and can get pretty slow...
I have a table 4 columns - Code, Status, EffectiveDate (EFF_DT), EndDate (END_DT). All the columns are Varchar2 type. EFF_DT and END_DT has ISO format date (YYYY-MM-DD) with NULL values for few rows. Need to get the rows which has END_DT greater than today's date.
While executing the below query, it returns all the Not NULL rows for END_DT. Do not compare the END_DT at all.
select code, status, EFF_DT, END_DT
from (
select CODE, EFF_DT, Status,to_date("END_DT" ,'YYYY-MM-DD' ) as END_DT
from xxx.ZZZ
) TAB
where to_date(TAB.END_DT ,'DD-MM-YY' ) > to_date(CAST(CURRENT_TIMESTAMP as Date), 'DD-MM-YY')
ORDER BY 1 ASC
But the below query compares the END_DT and returns the result properly -
SELECT "TAB"."CODE" , "TAB"."STATUS" AS "STATUS" , "TAB"."EFF_DT" , "TAB"."END_DT"
FROM xxx.ZZZ "TAB"
WHERE ( (to_date("TAB"."END_DT",'YYYY-MM-DD') > to_date(CAST(CURRENT_TIMESTAMP as Date), 'YY-MM-DD')) )
ORDER BY 1 ASC
What is going wrong with the 1st query?
I see difference in return value of END_DT.
For the 1st query, the data is coming like -
while as for the 2nd query, the data is coming like
I am trying to assign 'A' to [Student Details].group based on this SELECT statement.
SELECT TOP (10) PERCENT [Person Id], [Given Names], Surname, Gpa, [Location Cd]
FROM [Student Details]
WHERE ([Location Cd] = 'PAR')
ORDER BY Gpa DESC
I can't figure out how to use a SELECT statement in an UPDATE statement.
Can someone please explain how to accomplish this?
I am using ASP .NET and MsSQL Server if it makes a difference.
Thanks
I'm assuming you want to update these records and then return them :
SELECT TOP (10) PERCENT [Person Id], [Given Names], Surname, Gpa, [Location Cd]
INTO #temp
FROM [Student Details]
WHERE ([Location Cd] = 'PAR')
ORDER BY Gpa DESC
update [Student Details] set group='A' where [person id] in(select [person id] from #temp)
select * from #temp
I'm also assuming person id is the PK of student details
Try this using CTE (Common Table Expression):
;WITH CTE AS
(
SELECT TOP 10 PERCENT [Group]
FROM [Student Details]
WHERE ([Location Cd] = 'PAR')
ORDER BY Gpa DESC
)
UPDATE CTE SET [Group] = 'A'
Is this you want?
Update top (10) Percent [Student Details] set [group] = 'A'
where [Location Cd] = 'PAR' AND [group] is null
I am trying to run query
select * from OS_Historystep where step_name = '011' and finish_date = max(finish_date) ;
But i am getting error that
ORA-00934: group function is not allowed here
00934. 00000 - "group function is not allowed here"
*Cause:
*Action:
Error at Line: 12 Column: 72
what i am doing wrong?
Thanks
You can't use an aggregate in a where clause. Also, you can't mix non-aggregated data and aggregated data from the same column in a single select. You'll need to use a sub-query:
select *
from OS_Historystep hs1
where step_name = '011'
and finish_date = (select max(finish_date)
from OS_Historystep hs2
where hs2.step_name = hs1.step_name);
you cannot reference an aggregate like that. you would either have to put a sub query up like below (assuming you wanted the max(finish_date) to mean the max finish date for step 011 and not the max finish date in the whole table (which may return no rows):
select *
from OS_Historystep
where step_name = '011'
and finish_date = (select max(finish_date)
from OS_Historystep
where step_name = '011');
or use an analytic function
select *
from (select s.*, rank() over (partition by step_name order by finish_date desc) rnk
from OS_Historystep s
where step_name = '011')
where rnk = 1;