Related
What is the best way to get count of rows and distinct rows in a single query?
To get distinct count we can use subquery like this:
select count(*) from
(
select distinct * from table
)
I have 15+ columns and have many duplicates rows as well and I want to calculate count of rows as well as distinct count of rows in one query.
More if I use this
select count(*) as Rowcount , count(distinct *) as DistinctCount from table
This will not give accurate results as count(distinct *) doesn't work.
Why don't you just put the subquery inside another query?
select count(*),
(select count(*) from (select distinct * from table))
from table;
create table tbl
(
col int
);
insert into tbl values(1),(2),(1),(3);
select count(*) as distinct_count, sum(sum) as all_count
from (
select count(col) sum from tbl group by col
)A
I think I have understood what you are looking for. You need to use some window function. So, you query should be look like =>
Select COUNT(*) OVER() YourRowcount ,
COUNT(*) OVER(Partition BY YourColumnofGroup) YourDistinctCount --Basic of the distinct count
FROM Yourtable
NEW Update
select top 1
COUNT(*) OVER() YourRowcount,
DENSE_RANK() OVER(ORDER BY YourColumn) YourDistinctCount
FROM Yourtable ORDER BY TT DESC
Note: This code is written sql server. Please check the code and let me know.
Trying to get an overall distinct count of the employees for a range of records which has a group by on it.
I've tried using the "over()" clause but couldn't get that to work. Best to explain using an example so please see my script below and wanted result below.
EDIT:
I should mention I'm hoping for a solution that does not use a sub-query based on my "sales_detail" table below because in my real example, the "sales_detail" table is a very complex sub-query.
Here's the result I want. Column "wanted_result" should be 9:
Sample script:
CREATE TEMPORARY TABLE [sales_detail] (
[employee] varchar(100),[customer] varchar(100),[startdate] varchar(100),[enddate] varchar(100),[saleday] int,[timeframe] varchar(100),[saleqty] numeric(18,4)
);
INSERT INTO [sales_detail]
([employee],[customer],[startdate],[enddate],[saleday],[timeframe],[saleqty])
VALUES
('Wendy','Chris','8/1/2019','8/12/2019','5','Afternoon','1'),
('Wendy','Chris','8/1/2019','8/12/2019','5','Morning','5'),
('Wendy','Chris','8/1/2019','8/12/2019','6','Morning','6'),
('Dexter','Chris','8/1/2019','8/12/2019','2','Mid','2.5'),
('Jennifer','Chris','8/1/2019','8/12/2019','4','Morning','2.75'),
('Lila','Chris','8/1/2019','8/12/2019','2','Morning','3.75'),
('Rita','Chris','8/1/2019','8/12/2019','2','Mid','1'),
('Tony','Chris','8/1/2019','8/12/2019','4','Mid','2'),
('Tony','Chris','8/1/2019','8/12/2019','1','Morning','6'),
('Mike','Chris','8/1/2019','8/12/2019','4','Mid','1.5'),
('Logan','Chris','8/1/2019','8/12/2019','3','Morning','6.25'),
('Blake','Chris','8/1/2019','8/12/2019','4','Afternoon','0.5')
;
SELECT
[timeframe],
SUM([saleqty]) AS [total_qty],
COUNT(DISTINCT [s].[employee]) AS [employee_count1],
SUM(COUNT(DISTINCT [s].[employee])) OVER() AS [employee_count2],
9 AS [wanted_result]
FROM (
SELECT
[employee],[customer],[startdate],[enddate],[saleday],[timeframe],[saleqty]
FROM
[sales_detail]
) AS [s]
GROUP BY
[timeframe]
;
If I understand correctly, you are simply looking for a COUNT(DISTINCT) for all employees in the table? I believe this query will return the results you are looking for:
SELECT
[timeframe],
SUM([saleqty]) AS [total_qty],
COUNT(DISTINCT [s].[employee]) AS [employee_count1],
(SELECT COUNT(DISTINCT [employee]) FROM [sales_detail]) AS [employee_count2],
9 AS [wanted_result]
FROM #sales_detail [s]
GROUP BY
[timeframe]
You can try this below option-
SELECT
[timeframe],
SUM([saleqty]) AS [total_qty],
COUNT(DISTINCT [s].[employee]) AS [employee_count1],
SUM(COUNT(DISTINCT [s].[employee])) OVER() AS [employee_count2],
[wanted_result]
-- select count form sub query
FROM (
SELECT
[employee],[customer],[startdate],[enddate],[saleday],[timeframe],[saleqty],
(select COUNT(DISTINCT [employee]) from [sales_detail]) AS [wanted_result]
--caculate the count with first sub query
FROM [sales_detail]
) AS [s]
GROUP BY
[timeframe],[wanted_result]
Use a trick where you only count each person on the first day they are seen:
select timeframe, sum(saleqty) as total_qty),
count(distinct employee) as employee_count1,
sum( (seqnum = 1)::int ) as employee_count2
9 as wanted_result
from (select sd.*,
row_number() over (partition by employee order by startdate) as seqnum
from sales_detail sd
) sd
group by timeframe;
Note: From the perspective of performance, your complex subquery is only evaluated once.
I'm looking get two things from a query, given a set of contraints:
The first match
The total number of matches
I can get the first match by:
SELECT TOP 1
ID,
ReportYear,
Name,
SignDate,
...
FROM Table
WHERE
...
ORDER BY ... //I can put in here which one I want to take
And then I can get the match count if I use
SELECT
MIN(ID),
MIN(ReportYear),
MIN(Name),
MIN(SignDate),
... ,
COUNT(*) as MatchCount
FROM Table
WHERE
...
GROUP BY
??? // I don't really want any grouping
I really want to avoid both grouping and using an aggregate function on all my results. This question SQL Server Select COUNT without using aggregate function or group by suggests the answer would be
SELECT TOP 1
ID,
ReportYear,
Name,
SignDate,
... ,
##ROWCOUNT as MatchCount
FROM Table
This works without the TOP 1, but when it's in there, ##ROWCOUNT = number of rows returned, which is 1. How can I get essentially the output of COUNT(*) (whatever's left after the where clause) without any grouping or need to aggregate all the columns?
What I don't want to do is repeat each of these twice, once for the first row and then again for the ##ROWCOUNT. I'm not finding a way I can properly use GROUP BY, because I strictly want the number of items that match my criteria, and I want columns that if I GROUPed them would throw this number off - unless I'm misunderstanding GROUP BY.
Assuming you are using a newish version of SQL Server (2008+ from memory) then you can use analytic functions.
Simplifying things somewhat, they are a way of way of doing an aggregate over a set of data instead of a group - an extension on basic aggregates.
Instead of this:
SELECT
... ,
COUNT(*) as MatchCount
FROM Table
WHERE
...
You do this:
SELECT
... ,
COUNT(*) as MatchCount OVER (PARTITION BY <group fields> ORDER BY <order fields> )
FROM Table
WHERE
...
GROUP BY
Without actually running some code, I can't recall exactly which aggregates that you can't use in this fashion. Count is fine though.
Well, you can use OVER clause, which is an window function.
SELECT TOP (1)
OrderID, CustID, EmpID,
COUNT(*) OVER() AS MatchCount
FROM Sales.Orders
WHERE OrderID % 2 = 1
ORDER BY OrderID DESC
Try next query:
select top 1
*, count(*) over () rowsCount
from
(
select
*, dense_rank() over (order by ValueForOrder) n
from
myTable
) t
where
n = 1
If i perform a standard query in SQLite:
SELECT * FROM my_table
I get all records in my table as expected. If i perform following query:
SELECT *, 1 FROM my_table
I get all records as expected with rightmost column holding '1' in all records. But if i perform the query:
SELECT *, COUNT(*) FROM my_table
I get only ONE row (with rightmost column is a correct count).
Why is such results? I'm not very good in SQL, maybe such behavior is expected? It seems very strange and unlogical to me :(.
SELECT *, COUNT(*) FROM my_table is not what you want, and it's not really valid SQL, you have to group by all the columns that's not an aggregate.
You'd want something like
SELECT somecolumn,someothercolumn, COUNT(*)
FROM my_table
GROUP BY somecolumn,someothercolumn
If you want to count the number of records in your table, simply run:
SELECT COUNT(*) FROM your_table;
count(*) is an aggregate function. Aggregate functions need to be grouped for a meaningful results. You can read: count columns group by
If what you want is the total number of records in the table appended to each row you can do something like
SELECT *
FROM my_table
CROSS JOIN (SELECT COUNT(*) AS COUNT_OF_RECS_IN_MY_TABLE
FROM MY_TABLE)
I'm not sure if this is even a good question or not.
I have a complex query with lot's of unions that searches multiple tables for a certain keyword (user input). All tables in which there is searched are related to the table book.
There is paging on the resultset using LIMIT, so there's always a maximum of 10 results that get withdrawn.
I want an extra column in the resultset displaying the total amount of results found however. I do not want to do this using a separate query. Is it possible to add a count() column to the resultset that counts every result found?
the output would look like this:
ID Title Author Count(...)
1 book_1 auth_1 23
2 book_2 auth_2 23
4 book_4 auth_.. 23
...
Thanks!
This won't add the count to each row, but one way to get the total count without running a second query is to run your first query using the SQL_CALC_FOUND_ROWS option and then select FOUND_ROWS(). This is sometimes useful if you want to know how many total results there are so you can calculate the page count.
Example:
select SQL_CALC_FOUND_ROWS ID, Title, Author
from yourtable
limit 0, 10;
SELECT FOUND_ROWS();
From the manual:
http://dev.mysql.com/doc/refman/5.1/en/information-functions.html#function_found-rows
The usual way of counting in a query is to group on the fields that are returned:
select ID, Title, Author, count(*) as Cnt
from ...
group by ID, Title, Author
order by Title
limit 1, 10
The Cnt column will contain the number of records in each group, i.e. for each title.
Regarding second query:
select tbl.id, tbl.title, tbl.author, x.cnt
from tbl
cross join (select count(*) as cnt from tbl) as x
If you will not join to other table(s):
select tbl.id, tbl.title, tbl.author, x.cnt
from tbl, (select count(*) as cnt from tbl) as x
My Solution:
SELECT COUNT(1) over(partition BY text) totalRecordNumber
FROM (SELECT 'a' text, id_consult_req
FROM consult_req cr);
If your problem is simply the speed/cost of doing a second (complex) query I would suggest you simply select the resultset into a hash-table and then count the rows from there while returning, or even more efficiently use the rowcount of the previous resultset, then you do not even have to recount
This will add the total count on each row:
select count(*) over (order by (select 1)) as Cnt,*
from yourtable
Here is your answare:
SELECT *, #cnt count_rows FROM (
SELECT *, (#cnt := #cnt + 1) row_number FROM your_table
CROSS JOIN (SELECT #cnt := 0 AS variable) t
) t;
You simply cannot do this, you'll have to use a second query.