SQL query for counting records per month

Question

I have a dataset I need to build for number of visits per month for particular user. I have a SQL table which contains these fields:

• User nvarchar(30)
• DateVisit datetime

What I want to achieve now is to get all the visits grouped by month for each user, something like at the picture:

I started the query, I am able to get the months and the total sum of visits for that month (not split by user) with this query;

select  [1] AS January,
  [2] AS February,
  [3] AS March,
  [4] AS April,
  [5] AS May,
  [6] AS June,
  [7] AS July,
  [8] AS August,
  [9] AS September,
  [10] AS October,
  [11] AS November, 
  [12] AS December 
from
(
SELECT MONTH(DateVisit) AS month, [User] FROM UserVisit
) AS t
PIVOT (
COUNT([User])
  FOR month IN([1], [2], [3], [4], [5],[6],[7],[8],[9],[10],[11],[12])
) p

With the query above I am getting this result:

Now I want to know how I can add one more column for user and split the values by user.

Answer 1

You were nearly there: Just add the user to the select list:

select [Usr],
  [1] AS January,
  [2] AS February,
  [3] AS March,
  [4] AS April,
  [5] AS May,
  [6] AS June,
  [7] AS July,
  [8] AS August,
  [9] AS September,
  [10] AS October,
  [11] AS November, 
  [12] AS December 
from
(
SELECT MONTH(DateVisit) AS month, [User], [User] as [Usr] FROM UserVisit
) AS t
PIVOT (
COUNT([User])
  FOR month IN([1], [2], [3], [4], [5],[6],[7],[8],[9],[10],[11],[12])
) p

Answer 2

Okay, both solutions look good. The answer by Ali works but I would use a SUM() function instead, I hate NULLS. Let's try both and see the query plans versus execution times.

I always create a test table with data so that I do not give the user, Aziale, bad answers.

The code below is not the prettiest but it does set up a test case. I made a database in tempdb called user_visits. For each month, I used a for loop to add the users and give them the create start date for the month.

Now that we have data, we can play.

-- Drop the table
drop table tempdb.dbo.user_visits
go

-- Create the table
create table tempdb.dbo.user_visits
(
    uv_id int identity(1, 1),
    uv_visit_date smalldatetime,
    uv_user_name varchar(30)
);
go

-- January data
declare @cnt int = 1;
while @cnt <= 103
begin
    if (@cnt <= 21) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130101', 'Patrick');

    if (@cnt <= 44) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130101', 'Barbara');

    if (@cnt <= 65) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130101', 'Danielle');

    if (@cnt <= 103) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130101', 'John');

    set @cnt = @cnt + 1
end
go

-- February data
declare @cnt int = 1;
while @cnt <= 99
begin
    if (@cnt <= 29) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130201', 'Patrick');

    if (@cnt <= 42) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130201', 'Barbara');

    if (@cnt <= 55) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130201', 'Danielle');

    if (@cnt <= 99) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130201', 'John');

    set @cnt = @cnt + 1
end
go

-- March data
declare @cnt int = 1;
while @cnt <= 98
begin
    if (@cnt <= 25) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130301', 'Patrick');

    if (@cnt <= 46) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130301', 'Barbara');

    if (@cnt <= 75) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130301', 'Danielle');

    if (@cnt <= 98) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130301', 'John');

    set @cnt = @cnt + 1
end
go

-- April data
declare @cnt int = 1;
while @cnt <= 91
begin
    if (@cnt <= 32) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130401', 'Patrick');

    if (@cnt <= 48) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130401', 'Barbara');

    if (@cnt <= 60) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130401', 'Danielle');

    if (@cnt <= 91) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130401', 'John');

    set @cnt = @cnt + 1
end
go

-- May data
declare @cnt int = 1;
while @cnt <= 120
begin
    if (@cnt <= 40) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130501', 'Patrick');

    if (@cnt <= 41) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130501', 'Barbara');

    if (@cnt <= 70) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130501', 'Danielle');

    if (@cnt <= 120) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130501', 'John');

    set @cnt = @cnt + 1
end
go

-- June data
declare @cnt int = 1;
while @cnt <= 103
begin
    if (@cnt <= 17) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130601', 'Patrick');

    if (@cnt <= 45) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130601', 'Barbara');

    if (@cnt <= 62) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130601', 'Danielle');

    if (@cnt <= 103) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130601', 'John');

    set @cnt = @cnt + 1
end
go

-- July data
declare @cnt int = 1;
while @cnt <= 99
begin
    if (@cnt <= 20) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130701', 'Patrick');

    if (@cnt <= 43) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130701', 'Barbara');

    if (@cnt <= 66) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130701', 'Danielle');

    if (@cnt <= 99) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130701', 'John');

    set @cnt = @cnt + 1
end
go

-- August data
declare @cnt int = 1;
while @cnt <= 98
begin
    if (@cnt <= 26) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130801', 'Patrick');

    if (@cnt <= 47) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130801', 'Barbara');

    if (@cnt <= 71) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130801', 'Danielle');

    if (@cnt <= 98) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130801', 'John');

    set @cnt = @cnt + 1
end
go

-- September data
declare @cnt int = 1;
while @cnt <= 91
begin
    if (@cnt <= 25) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130901', 'Patrick');

    if (@cnt <= 49) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130901', 'Barbara');

    if (@cnt <= 59) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130901', 'Danielle');

    if (@cnt <= 91) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20130901', 'John');

    set @cnt = @cnt + 1
end
go

-- October data
declare @cnt int = 1;
while @cnt <= 120
begin
    if (@cnt <= 25) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20131001', 'Patrick');

    if (@cnt <= 40) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20131001', 'Barbara');

    if (@cnt <= 73) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20131001', 'Danielle');

    if (@cnt <= 120) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20131001', 'John');

    set @cnt = @cnt + 1
end
go

-- November data
declare @cnt int = 1;
while @cnt <= 101
begin
    if (@cnt <= 32) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20131101', 'Patrick');

    if (@cnt <= 50) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20131101', 'Barbara');

    if (@cnt <= 65) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20131101', 'Danielle');

    if (@cnt <= 101) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20131101', 'John');

    set @cnt = @cnt + 1
end
go

-- December data
declare @cnt int = 1;
while @cnt <= 90
begin
    if (@cnt <= 40) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20131201', 'Patrick');

    if (@cnt <= 52) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20131201', 'Barbara');

    if (@cnt <= 61) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20131201', 'Danielle');

    if (@cnt <= 90) 
        insert into tempdb.dbo.user_visits 
        (uv_visit_date, uv_user_name)
        values ('20131201', 'John');

    set @cnt = @cnt + 1
end
go

Please do not use reserve words in coding as column names - IE - month is a reserve word.

The code below gives you the correct answer.

-- Grab the data (1)
select 
  my_user, 
  [1] AS January,
  [2] AS Febrary,
  [3] AS March,
  [4] AS April,
  [5] AS May,
  [6] AS June,
  [7] AS July,
  [8] AS August,
  [9] AS September,
  [10] AS October,
  [11] AS November, 
  [12] AS December 
from
(
  SELECT MONTH(uv_visit_date) AS my_month, uv_user_name as my_user FROM tempdb.dbo.user_visits
) AS t
PIVOT (
  COUNT(my_month)
  FOR my_month IN([1], [2], [3], [4], [5],[6],[7],[8],[9],[10],[11],[12])
) as p

-- Grab the data (2)
SELECT  uv_user_name
       , SUM(CASE WHEN  MONTH(uv_visit_date) = 1 THEN 1 ELSE 0 END) January
       , SUM(CASE WHEN  MONTH(uv_visit_date) = 2 THEN 1 ELSE 0 END) Feburary
       , SUM(CASE WHEN  MONTH(uv_visit_date) = 3 THEN 1 ELSE 0 END) March
       , SUM(CASE WHEN  MONTH(uv_visit_date) = 4 THEN 1 ELSE 0 END) April
       , SUM(CASE WHEN  MONTH(uv_visit_date) = 5 THEN 1 ELSE 0 END) May
       , SUM(CASE WHEN  MONTH(uv_visit_date) = 6 THEN 1 ELSE 0 END) June
       , SUM(CASE WHEN  MONTH(uv_visit_date) = 7 THEN 1 ELSE 0 END) July
       , SUM(CASE WHEN  MONTH(uv_visit_date) = 8 THEN 1 ELSE 0 END) August
       , SUM(CASE WHEN  MONTH(uv_visit_date) = 9 THEN 1 ELSE 0 END) September
       , SUM(CASE WHEN  MONTH(uv_visit_date) = 10 THEN 1 ELSE 0 END) October
       , SUM(CASE WHEN  MONTH(uv_visit_date) = 11 THEN 1 ELSE 0 END) November
       , SUM(CASE WHEN  MONTH(uv_visit_date) = 12 THEN 1 ELSE 0 END) December
FROM tempdb.dbo.user_visits
GROUP BY uv_user_name

When doing this type of analysis, always clear the cache/buffers and get the I/O.

-- Show time & i/o
SET STATISTICS TIME ON
SET STATISTICS IO ON
GO

-- Remove clean buffers & clear plan cache
CHECKPOINT 
DBCC DROPCLEANBUFFERS 
DBCC FREEPROCCACHE
GO


-- Solution 1
SQL Server parse and compile time: 
   CPU time = 0 ms, elapsed time = 42 ms.

(4 row(s) affected)
Table 'Worktable'. Scan count 0, logical reads 0, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'user_visits'. Scan count 1, logical reads 11, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.

 SQL Server Execution Times:
   CPU time = 16 ms,  elapsed time = 5 ms.

-- Solution 2
SQL Server parse and compile time: 
   CPU time = 0 ms, elapsed time = 0 ms.

(4 row(s) affected)
Table 'Worktable'. Scan count 0, logical reads 0, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'user_visits'. Scan count 1, logical reads 11, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.

 SQL Server Execution Times:
   CPU time = 16 ms,  elapsed time = 5 ms.

Both solutions have the same number of reads, work table, etc. However, the SUM() solution has one less operator.

I am going to give both people who answered a thumbs up +1!!