Given a table (mytable) containing a numeric field (mynum), how would one go about writing an SQL query which summarizes the table's data based on ranges of values in that field rather than each distinct value?
For the sake of a more concrete example, let's make it intervals of 3 and just "summarize" with a count(*), such that the results tell the number of rows where mynum is 0-2.99, the number of rows where it's 3-5.99, where it's 6-8.99, etc.
The idea is to compute some function of the field that has constant value within each group you want:
select count(*), round(mynum/3.0) foo from mytable group by foo;
I do not know if this is applicable to mySql, anyway in SQL Server I think you can "simply" use group by in both the select list AND the group by list.
Something like:
select
CASE
WHEN id <= 20 THEN 'lessthan20'
WHEN id > 20 and id <= 30 THEN '20and30' ELSE 'morethan30' END,
count(*)
from Profiles
where 1=1
group by
CASE
WHEN id <= 20 THEN 'lessthan20'
WHEN id > 20 and id <= 30 THEN '20and30' ELSE 'morethan30' END
returns something like
column1 column2
---------- ----------
20and30 3
lessthan20 3
morethan30 13
Related
I want to do something like this
this works
Select ID, number, cost from table order by number
number can be 2-xtimes but the cost and the same
1 A33 66.50
2 A34 73.50
3 A34 73.50
But I want to have
1 A33 66.50
2 A34 73.50
3 A34 0
I want to change it in the Sql to 0
I tried distinct or if then else.
I want to do something like this
declare #oldcost int;
Select ID, number,
if(cost=#oldcost) then
cost=0;
else
cost=cost;
end if
#oldcost=cost;
from table order by number
How can I do it in SQL?
You can use window functions and a case expression:
select ID, number,
(case when row_number() over (partition by number order by id) = 1
then cost else 0
end) as cost
from table
order by number, id;
Note that SQL generally does not take ordering into account, so results can be returned in any order -- and even with an order by, rows with the same keys can be in any order (and in different orders on different executions).
Hence, the order by includes id as well as number so you get the cost on the "first" row for each number.
Is it possible to get closest(smaller) value of the same id in MS Access database?
It only need one expression, but I don't know how to write it properly.
Should looks like this:
ID Value Value2
1 10 0
2 5 0
1 20 10
1 50 20
2 15 5
...and so on..........
I have tried to use Dlookup and Max functions but I failed.
Thank you for any help.
You seem to want the previous value. There is no way to do this unless you have a column specifying the ordering. If so:
select t.*,
(select top (1) t2.value
from t as t2
where t2.? < t.?
order by t2.? desc
) as prev_value
from t;
The ? is for the column that specifies the ordering.
I have a table that looks like the following but also has more columns that are not needed for this instance.
ID DATE Random
-- -------- ---------
1 4/12/2015 2
2 4/15/2015 2
3 3/12/2015 2
4 9/16/2015 3
5 1/12/2015 3
6 2/12/2015 3
ID is the primary key
Random is a foreign key but i am not actually using table it points to.
I am trying to design a query that groups the results by Random and Date and select the MAX Date within the grouping then gives me the associated ID.
IF i do the following query
select top 100 ID, Random, MAX(Date) from DateBase group by Random, Date, ID
I get duplicate Randoms since ID is the primary key and will always be unique.
The results i need would look something like this
ID DATE Random
-- -------- ---------
2 4/15/2015 2
4 9/16/2015 3
Also another question is there could be times where there are many of the same date. What will MAX do in that case?
You can use NOT EXISTS() :
SELECT * FROM YourTable t
WHERE NOT EXISTS(SELECT 1 FROM YourTable s
WHERE s.random = t.random
AND s.date > t.date)
This will select only those who doesn't have a bigger date for corresponding random value.
Can also be done using IN() :
SELECT * FROM YourTable t
WHERE (t.random,t.date) in (SELECT s.random,max(s.date)
FROM YourTable s
GROUP BY s.random)
Or with a join:
SELECT t.* FROM YourTable t
INNER JOIN (SELECT s.random,max(s.date) as max_date
FROM YourTable s
GROUP BY s.random) tt
ON(t.date = tt.max_date and s.random = t.random)
In SQL Server you could do something like the following,
select a.* from DateBase a inner join
(select Random,
MAX(dt) as dt from DateBase group by Random) as x
on a.dt =x.dt and a.random = x.random
This method will work in all versions of SQL as there are no vendor specifics (you'll need to format the dates using your vendor specific syntax)
You can do this in two stages:
The first step is to work out the max date for each random:
SELECT MAX(DateField) AS MaxDateField, Random
FROM Example
GROUP BY Random
Now you can join back onto your table to get the max ID for each combination:
SELECT MAX(e.ID) AS ID
,e.DateField AS DateField
,e.Random
FROM Example AS e
INNER JOIN (
SELECT MAX(DateField) AS MaxDateField, Random
FROM Example
GROUP BY Random
) data
ON data.MaxDateField = e.DateField
AND data.Random = e.Random
GROUP BY DateField, Random
SQL Fiddle example here: SQL Fiddle
To answer your second question:
If there are multiples of the same date, the MAX(e.ID) will simply choose the highest number. If you want the lowest, you can use MIN(e.ID) instead.
With the sql below I count how many records I have in tableB for each code. The total field is assigned the result of the count and the code the code field of the record.
SELECT
"count" (*) as total,
tableB."code" as code
FROM
tableB
WHERE
tableB.code LIKE '%1'
GROUP BY
tableB.code
In tableA I have a sequence field and I update with the result of total (obtained in the previous sql) plus 1 Do this for each code.
I tried this and it did not work, can someone help me?
UPDATE tableA
SET tableA.sequence = (tableB.total + 1) where tableA."code" = tableB.code
FROM
(
SELECT
"count" (*) as total,
tableB."code" as code
FROM
tableB
WHERE
tableB.code LIKE '%1'
GROUP BY
tableB.code
)
I edited for my tables are as mostar believe facillita understanding of my need
tableA
code sequence
100 null
200 null
table B
code sequence
100 1
100 2
100 3
100 4
......
100 17
200 1
200 2
200 3
200 4
......
200 23
Need to update the sequence blank field in tableA with the number 18 to code = 100
Need to update the sequence blank field in tableA with the number 24 to code = 200
This assumes that code is unique in table_a:
with max_seq as (
select code,
max(sequence) + 1 as max_seq
from table_b
group by code
)
update table_a
set sequence = ms.max_seq
from max_seq ms
where table_a.code = ms.code;
SQLFiddle example: http://sqlfiddle.com/#!15/745a7/1
UPDATE tbl_a a
SET sequence = b.next_seq
FROM (
SELECT code, max(sequence) + 1 AS next_seq
FROM tbl_b
GROUP BY code
) b
WHERE a.code = b.code;
SQL Fiddle.
Only columns of the target table can be updated. It would not make sense to table-qualify those. Consequently, this is not allowed.
Every subquery must have a table alias for the derived table.
I would not use a CTE for a simple UPDATE like this. A subquery in the FROM clause is typically simpler and faster.
No point in double-quoting the aggregate function count(). No pint in double-quoting perfectly legal, lower case identifiers, either. No point in table-qualifying columns in a subquery on a single table in a plain SQL command (no harm either).
You don't need a WHERE condition, since you want to UPDATE all rows (as it seems). Note that only row with matching code are updated. Other rows in tbl_b remain untouched.
Basically you need to read the manual about UPDATE before you try any of this.
I've been stuck for quite a while now trying to get this query to work.
Here's the setup:
I have a [Notes] table that contains a nonunique (Number) column and a nonunique (Result) column. I'm looking to create a SELECT statement that will display each distinct (Number) value where the count of the {(Number), (Result)} tuple where Result = 'NA' is > 25.
Number | Result
100 | 'NA'
100 | 'TT'
101 | 'NA'
102 | 'AM'
100 | 'TT'
200 | 'NA'
200 | 'NA'
201 | 'NA'
Basically, have an autodialer that calls a number and returns a code depending on the results of the call. We want to ignore numbers that have had an 'NA'(no answer) code returned more than 25 times.
My basic attempts so far have been similar to:
SELECT DISTINCT n1.Number
FROM Notes n1
WHERE (SELECT COUNT(*) FROM Notes n2
WHERE n1.Number = n2.Number and n1.Result = 'NA') > 25
I know this query isn't correct, but in general I'm not sure how to relate the DISTINCT n1.Number from the initial select to the Number used in the subquery COUNT. Most examples I see aren't actually doing this by adding a condition to the COUNT returned. I haven't had to touch too much SQL in the past half decade, so I'm quite rusty.
you can do it like this :
SELECT Number
FROM Notes
WHERE Result = 'NA'
GROUP BY Number
HAVING COUNT(Result) > 25
Try this:
SELECT Number
FROM (
SELECT Number, Count(Result) as CountNA
FROM Notes
WHERE Result = 'NA'
GROUP BY Number
)
WHERE CountNA > 25
EDIT: depending on SQL product, you may need to give the derived table a table correlation name e.g.
SELECT DT1.Number
FROM (
SELECT Number, Count(Result) as CountNA
FROM Notes
WHERE Result = 'NA'
GROUP
BY Number
) AS DT1 (Number, CountNA)
WHERE DT1.CountNA > 25;