I have a table that has an integer column from which I am trying to get a few counts from. Basically I need four separate counts from the same column. The first value I need returned is the count of how many records have an integer value stored in this column between two values such as 213 and 9999, including the min and max values. The other three count values I need returned are just the count of records between different values of this column. I've tried doing queries like...
SELECT (SELECT Count(ID) FROM view1 WHERE ((MyIntColumn BETWEEN 213 AND 9999));)
AS Value1, (SELECT Count(ID) FROM FROM view1 WHERE ((MyIntColumn BETWEEN 500 AND 600));) AS Value2 FROM view1;
So there are for example, ten records with this column value between 213 and 9999. The result returned from this query gives me 10, but it gives me the same value of 10, 618 times which is the number of total records in the table. How would it be possible for me to only have it return one record of 10 instead?
Use the Iif() function instead of CASE WHEN
select Condition1: iif( ), condition2: iif( ), etc
P.S. : What I used to do when working with Access was have the iif() resolve to 1 or 0 and then do a SUM() to get the counts. Roundabout but it worked better with aggregation since it avoided nulls.
SELECT
COUNT(CASE
WHEN MyIntColumn >= 213 AND MyIntColumn <= 9999
THEN MyIntColumn
ELSE NULL
END) AS FirstValue
, ??? AS SecondValue
, ??? AS ThirdValue
, ??? AS FourthValue
FROM Table
This doesn't need nesting or CTE or anything. Just define via CASE your condition within COUNTs argument.
I dont really understand what You want in the second, third an fourth column. Sounds to me, its very similar to the first one.
Reformatted, your query looks like:
SELECT (
SELECT Count(ID)
FROM view1
WHERE MyIntColumn BETWEEN 213 AND 9999
) AS Value1
FROM view1;
So you are selecting a subquery expression that is not related to the outer query. For each row in view1, you calculate the number of rows in view1.
Instead, try to do the calculation once. You just have to remove your outer query:
SELECT Count(ID)
FROM view1
WHERE MyIntColumn BETWEEN 213 AND 9999;
OLEDB Connection in MS Access does not support key words CASE and WHEN .
You can only use iif() function to count two, three.. values in same columns
SELECT Attendance.StudentName, Count(IIf([Attendance]![Yes_No]='Yes',1,Null)) AS Yes, Count(IIf([Attendance]![Yes_No]='No',1,Null)) AS [No], Count(IIf([Attendance]![Yes_No]='Not',1,Null)) AS [Not], Count(IIf([Attendance]![Yes_No],1,Null)) AS Total
FROM Attendance
GROUP BY Attendance.StudentName;
Related
In Firebird 2.5 I have a table of hardware device events; each row contains a timestamp, a device ID and an integer status of the event. I need to retrieve a rowset of the subset of IDs with non-0 statuses and the number of instances of the non-0 events for each ID, within a specified date range. I can get the subset of IDs with non-0 statuses in the specified date range, but I can't figure out how to get the count of non-0-status rows associated with each ID in the same rowset. I'd prefer to do this in a query rather than a stored proc, if possible.
The table is:
RPR_HISTORY
TSTAMP timestamp
RPRID integer
PARID integer
LASTRES integer
LASTCUR float
The rowset I want is like
RPRID ERRORCOUNT
-------------------
18 4
19 2
66 7
The query
select distinct RPRID from RPR_HISTORY
where (LASTRES <> 0)
and (TSTAMP >= :STARTSTAMP);
gives me the IDs I'm looking for, but obviously not the count of non-0-status rows for each ID. I've tried a bunch of combinations of nested queries derived from the above; all generate errors, usually on grouping or aggregation errors. It seems like a straightforward thing to do but is just escaping me.
Got it! The query
select rh.RPRID, count(rh.RPRID) from RPR_HISTORY rh
where (rh.LASTRES <> 0)
and (rh.TSTAMP >= :STARTSTAMP)
and rh.RPRID in
(select distinct rd.RPRID from RPR_HISTORY rd where rd.LASTRES <> 0)
group by rh.RPRID;
returns the rowset I need.
I have table like this:
And lets say I want to have in another occurence of login eg. 1234 i would like to have instead of 275 value of 0, the same for 3678 instead of 300 i would like to have 0. I want to have profit/loss only for first occurence in the table. Is this somehow possible to do it in SQL?
If you only want to keep the highest / lowest, you can join the table with itself.
If you only want the first (as in lowest row number) occurance you can use a window function and update all occurances > 1
UPDATE SUB
set profit = 0
FROM (
SELECT
profit,
ROW_NUMBER() OVER (PARTITION BY Login ORDER BY Login) as cnt
FROM table
) SUB
WHERE SUB.cnt > 1
In Standard SQL, you can use:
update t
set profit = 0
where profit > (select max(profit) from t t2 where t2.login = t.login);
Note that specific databases may have alternative ways to writing this. However, your question does not have a database tag.
Also, this assumes that your table does not have duplicates. Unfortunately, duplicates would be problematic if these are the only two columns in the table.
I have a table match which looks like this (please see attached image). I wanted to retrieve a dataset that had a column of average values for home_goal and away_goal using this code
SELECT
m.country_id,
m.season,
m.home_goal,
m.away_goal,
AVG(m.home_goal + m.away_goal) AS avg_goal
FROM match AS m;
However, I got this error
column "m.country_id" must appear in the GROUP BY clause or be used in an aggregate function
LINE 3: m.country_id,
My question is: why was GROUP BY clause required? Why couldn't SQL know how to take average of two columns row by row?
Thank you.
try this:
SELECT
m.country_id,
m.season,
m.home_goal,
m.away_goal,
(m.home_goal + m.away_goal)/2 AS avg_goal
FROM match AS m;
You have been asked for the group_by as avg() much like sum() work on multiple values of one column where you classify all columns that are not a columns wise operation in the group by
You are looking to average two distinct columns - it is a row-wise operations instead of column-wise
how to take average of two columns row by row?
You don't use AVG() for this; it is an aggregate function, that operates over a set of rows. Here, it seems like you just want a simple math computation:
SELECT
m.country_id,
m.season,
m.home_goal,
m.away_goal,
(m.home_goal + m.away_goal) / 2.0 AS avg_goal
FROM match AS m;
Note the decimal denominator (2.0): this avoids integer division in databases that implement it.
Avg in the context of the function mentioned above is calculating the average of the values of the columns and not the average of the two values in the same row. It is an aggregate function and that’s why the group by clause is required.
In order to take the average of two columns in the same row you need to divide by 2.
Let's consider the following table:
CREATE TABLE Numbers([x] int, [y] int, [category] nvarchar(10));
INSERT INTO Numbers ([x], [y], [category])
VALUES
(1, 11, 'odd'),
(2, 22, 'even'),
(3, 33, 'odd'),
(4, 44, 'even');
Here is an example of using two aggregate functions - AVG and SUM - with GROUP BY:
SELECT
Category,
AVG(x) as avg_x,
AVG(x+y) as avg_xy,
SUM(x) as sum_x,
SUM(x+y) as sum_xy
FROM Numbers
GROUP BY Category
The result has two rows:
Category avg_x avg_xy sum_x sum_xy
even 3 36 6 72
odd 2 24 4 48
Please note that Category is available in the SELECT part because the results are GROUP BY'ed by it. If a GROUP BY is not specified then the result would be 1 row and Category is not available (which value should be displayed if we have sums and averages for multiple rows with different caetories?).
What you want is to compute a new column and for this you don't use aggregate functions:
SELECT
(x+y)/2 as avg_xy,
(x+y) as sum_xy
FROM Numbers
This returns all rows:
avg_xy sum_xy
6 12
12 24
18 36
24 48
If your columns are integers don't forget to handle rounding, if needed. For example (CAST(x AS DECIMAL)+y)/2 as avg_xy,
The simple arithmetic calculation:
(m.home_goal + m.away_goal) / 2.0
is not exactly equivalent to AVG(), because NULL values mess it up. Databases that support lateral joins provide a pretty easy (and efficient) way to actually use AVG() within a row.
The safe version looks like:
(coalesce(m.home_goal, 0) + coalesce(m.away_goal, 0)) /
nullif( (case when m.home_goal is not null then 1 else 0 end +
case when m.away_goal is not null then 1 else 0 end
), 0
)
Some databases have syntax extensions that allow the expression to be simplified.
Given a table of random numbers as follows:
** Person table schema **
Name
Marks1
Marks2
I want to return a table with similar structure and headings, where if the sum of a column is odd, the column shows the maximum value for that column, and when the sum is even, it shows the minimum value by using a case statement.
** output table schema **
Marks1
Marks2
I've tried the following code.
select Marks1,Marks2 ,
(case
when mod(sum(Marks1),2)=0 then
min(Marks1)
else max(Marks1)
end) as Marks1 ,
(case
when mod(sum(Marks2),2)=0 then
min(Marks2)
else max(Marks2)
end) as Marks2
from numbers
group by Marks1;
Sample output -
TABLE
Ash 56 45
David 45 35
Output -
56 35
As 56+45 = 101 odd number so output 56(max number). Whereas in marks2 column, 45+35 =80, even number so output 35(min number).
Can anyone tell me what's wrong with it? Thanks in advance.
Use a CTE to get your min(), max(), and sum() values. Then use case to determine what values to display.
Since your problem statement and sample results do not match, I followed your sample results to return max() on an odd sum(). You can switch this by changing the two case statements from 1 to 0.
Working fiddle
with totals as (
select sum(marks1) as marks1sum,
min(marks1) as marks1min,
max(marks1) as marks1max,
sum(marks2) as marks2sum,
min(marks2) as marks2min,
max(marks2) as marks2max
from numbers
)
select case mod(marks1sum, 2)
when 1 then marks1max
else marks1min
end as marks1,
case mod(marks2sum, 2)
when 1 then marks2max
else marks2min
end as marks2
from totals;
You are reusing marks1 and marks2 when aliasing your third and fourth column which is colliding. Try using different name.
I have 2 row data which I want to make it to be 2 column,
I tried union syntax but it didn't work.
Here is the data I have:
breed 1 breed2
I tried to convert it with this sql
select a.breed union a.breed
but it didn't work.
Here is what you want from the SQL:
breed1,breed2
SELECT
[breed1],
[breed2]]
FROM
(
SELECT 'breed1' myColumn
union
select 'breed2'
) AS SourceTable
PIVOT
(
AVG(mySecondColumn) FOR
myColumn IN ([breed1], [breed2]])
) AS PivotTable;
You can use a self join. This needs a way to pair rows together (so if you have four rows you get 1 and 2 in one result and 3 and 4 in the other rather than another combination).
I'm going to assume you have sequentially numbered rows in an Id column and an odd numbered row is paired with the one greater even Id:
select odd.Data as 'First', even.Data as 'Second'
from TheData odd
inner join TheData even on odd.Id+1 = even.Id
where odd.Id % 2 = 1;
More generally for more columns use of pivot is more flexible.
How about an aggregation query?
select min(breed) as breed1, max(breed) as breed2
from t;