Random Row Number Selection - c#

I am working on a website that does random selections of employees for random drug test. I am trying to figure out a report/ code using SQL Server 2008, ASP.NET, and C#.
Here is an example of what I have worked on so far:
I need to do is generate a report of all employees for a specific company where the employees are assign a number. Example of this code is as follows:
SELECT
dbo.names2.ssn, dbo.names2.firstname, dbo.names2.lastname,
ROW_NUMBER() over(order by dbo.names2.ssn) as RowNumber
FROM
dbo.names2
WHERE
dbo.names2.code = 8562
This query return 12 records number 1-12 with the Employees social security number, first name, and last name.
I now need to figure out a query so that when I go to my asp.net webpage and enter that I need 5 employees to be randomly tested that I get a query that returns the row number the employee is associated with in the query above on one page of the report, and on the second page of the report return the number assigned in the query above along with the employees SSN, First, and last name.
Thanks,
ty

I would ORDER BY NEWID() which generates a random GUID and SELECT TOP 5.
Edited. This query has 2 return results. 1 is the full list of employees and the other is just the list of 5 randomly selected numbers that corresponds to the rownum on the employee list.
IF (OBJECT_ID(N'tempdb..#tempTable') IS NOT NULL)
DROP TABLE #tempTable ;
CREATE TABLE #tempTable
(
RowNum INT ,
SSN VARCHAR(16) ,
FirstName VARCHAR(64) ,
LastName VARCHAR(64)
);
INSERT INTO [#tempTable]
([RowNum] ,
[SSN] ,
[FirstName] ,
[LastName]
)
SELECT ROW_NUMBER() OVER(ORDER BY dbo.names2.ssn) AS RowNum ,
dbo.names2.ssn ,
dbo.names2.firstname ,
dbo.names2.lastname
FROM dbo.names2
WHERE dbo.names2.code = 8562
SELECT [RowNum] ,
[SSN] ,
[FirstName] ,
[LastName]
FROM [#tempTable] AS tt
SELECT TOP 5 RowNum
FROM [#tempTable] AS tt
ORDER BY NEWID()

Related

TSQL Transpose a column of a table into a row

I have a temporary table with one column containing 3 pieces of data: Code, Date, and Quantity.
Example:
-------
FR123456
24/02/1988
500
I need to extract the data in this column into separate columns.
Example:
Code | Date | Quantity
--------- ----------- ----
FR123456 | 24/02/1988 | 500
I used this code:
SELECT [1], [2], [3]
FROM
(
SELECT row_number() OVER (ORDER BY splitdata DESC) AS Id, splitdata
FROM splitdata
) AS SourceTable
PIVOT
(
MIN (splitdata)
FOR id IN ([1], [2], [3])
) AS PivotTable;
The problem with it is that once the content of data changes, I may get the quantity content into the date column due to the aggregate function (MIN).
I assume this is SQL-Server related...
Your problem is: A SQL-Server table does not have any kind of implicit sort order. A simple SELECT * FROM SomeWhere can return in the sort order you've inserted your data, but can return completely different as well. The only chance to ensure a sort order is an ORDER BY at the outer-most query against a (set of) unique column(s).
You can create a sort order by kind of analysing your data:
This is a mockup-table with your test data:
DECLARE #mockup TABLE(YourColumn VARCHAR(100));
INSERT INTO #mockup VALUES
('FR123456')
,('24/02/1988')
,('500');
--The query will check the values if they can be casted to a number, to a date or not.
--This will be used to place a sort order to the values.
--I use 105 in CONVERT to enforce the dateformat dd-MM-yyyy
SELECT CASE WHEN TRY_CONVERT(DATE,YourColumn,105) IS NOT NULL THEN 2
ELSE CASE WHEN TRY_CAST(YourColumn AS INT) IS NOT NULL THEN 3 ELSE 1
END
END AS SortOrder
,YourColumn
FROM #mockup
ORDER BY SortOrder;
But if there are several triplets in your table, not just one as in your sample, I'm afraid you're lost...
Btw: Your own approach tries to do exactly the same:
SELECT row_number() OVER (order by splitdata desc)as Id
This will create kind of a sort order number, but it will be random (a quantity will appeare before or after the date depending on alphanumerical rules).
Hint
Add an IDENTITY column to your table. This will use an increasing number for any row the moment it is created. These values can be used to enforce the order as inserted (by using ORDER BY with this column).
UPDATE: Your query
SELECT [1], [2] , [3]
FROM
(SELECT CASE WHEN TRY_CONVERT(DATE,splitdata,105) IS NOT NULL THEN 2
ELSE CASE WHEN TRY_CAST(splitdata AS INT) IS NOT NULL THEN 3 ELSE 1
END
END AS Id , splitdata
from #mockup ) AS SourceTable
PIVOT
(
MIN (splitdata)
FOR id IN ([1], [2], [3])
) AS PivotTable;

Query database to display the total count of data based on current date and month from multiple tables

If I try to select 2 columns, i get an error message that says, Ambiguous column name 'signed_in'. Name of the tables are UserName and Meeting. Please help
select count(*)
FROM UserName, Meeting
where YEAR(signed_in ) = datepart(YEAR, getdate());
It means that the signed_in column is present in both UserName and Meeting tables. You need to prefix the column with a table name like this:
UserName.signed_in or Meeting.signed_in
Thank you all for your answers, I really appreciate.
I have sorted it out using the following code:
select
( select count() from UserName where YEAR(signed_in ) = datepart(YEAR, getdate()) )
+
( select count() from Meeting where YEAR(signed_in ) = datepart(YEAR, getdate()))
and the total count for the both tables display in one column, one row. totaling 7 which represents 5 from UserName table and 2 from Meeting table.

How to grab last row in database table with specific requirements?

Okay so I am accepting payments on my site (via Authorize.Net). The payment form redirects to a receipt page.
I will have a column in the database for an invoice code (column InvoiceCode), which is RRC0A in this instance. Then I will have another column for an 8 digit number (column InvoiceNumber). Then I will have InvoiceCode + InvoiceNumber = InvoiceId. For example, the InvoiceId will be RRC0A + 8 numbers. It will increment as such: 00000000, 00000001, 00000002, etc. Therefore the InvoiceId will be RRC0A00000001. I cannot simply increment the column in my database because there will be other InvoiceCodes that also start at 00000000.
I need to increment the InvoiceNumber by one when I add a new row. How can I grab the last InvoiceNumber that was entered into the database? It must be associated with the InvoiceCode RRC0A. This could occur when more than 1 person is making a payment, so I am not sure of the best way.
How can I pad the incrementing InvoiceNumber with 0's in front so that it is always 8 digits?
Using an identity and a computed column you can created you invoice numbers with the correct formatting at the time of insert.
CREATE TABLE [dbo].[Invoices](
[ID] [int] IDENTITY(1,1) NOT NULL,
[Code] [nchar](5) NOT NULL,
[InvoiceNumber] AS ([Code]+right('00000000'+CONVERT([nvarchar](10),[ID]),(8))) PERSISTED,
[Cost] [decimal](18, 2) NOT NULL,
CONSTRAINT [PK_Invoices] PRIMARY KEY CLUSTERED
(
[ID] ASC
)
)
sample bulk insert
INSERT INTO [dbo].[Invoices] ([Code], [Cost])
OUTPUT INSERTED.*
SELECT 'ABC01', 500 UNION ALL
SELECT 'ABC01', 501 UNION ALL
SELECT 'EFG23', 502 UNION ALL
SELECT 'RRAc1', 503 UNION ALL
SELECT 'ABC01', 504
output
ID Code InvoiceNumber Cost
1 ABC01 ABC0100000001 500.00
2 ABC01 ABC0100000002 501.00
3 EFG23 EFG2300000003 502.00
4 RRAc1 RRAc100000004 503.00
5 ABC01 ABC0100000005 504.00
When you insert your records you can get the ID and InvoiceNumber back at the same time.
The values are also persisted so they may be indexed as you would other columns.
SELECT InvoiceCode, MAX(InvoiceID)
FROM yourTable t
GROUP BY InvoiceCode
This should return the latest InvoiceID for each InvoiceCode, but you can add your own WHERE clause to filter it down
As for how to pad-left in sql, check out this answer.
A as in one column is just a bad design
Have composite PK
InvCode (varchar), InvInt (int)
declare #InvCode varchar(20) = 'RRC0A'
insert into invoice (InvCode, InvInt)
OUTPUT INSERTED.InvInt, INSERTED.InvCode
select #InvCode, isnull(max(InvInt),-1) + 1
from invoice
where InvCode = #InvCode;
The isnull will deal with the first one
A single statement is a transaction so I don't think two simultaneous could clobber
Even if they did the PK would be violated so the insert would fail
use a view or a computed column for the formatted invoice number
CREATE TABLE [dbo].[Invoice](
[InvCode] [varchar](10) NOT NULL,
[InvInt] [int] NOT NULL,
[Formatted] AS ([InvCode]+right('00000000'+CONVERT([nvarchar](10),[InvInt]),(8))),
CONSTRAINT [PK_Invoice] PRIMARY KEY CLUSTERED
(
[InvCode] ASC,
[InvInt] ASC
)
You can grab the last InvoiceNumber with a SELECT query.
You can pad the invoice number with the + sign to concatenate two strings, and then use RIGHT() to get the right-most 8 characters.

display multivalue attribute in gridView

I have a table studentPhone that looks like the following:
phone studentID
2345678 1
0562436720 1
2254754 2
0546218611 2
I want to display its data in a gridView with sqlDataSource select query as:
SELECT phone, studentID FROM studentPhone WHERE (studentID IN (1))
but the gridView display only the firstPhone of the specified studentID. How can I solve that to display all phones for a specific ID?
SELECT phone, studentID FROM studentPhone WHERE (studentID = 1 )
If you want to display all the phone number of one ID in a single column then you have to write a store procedure.
Example:
create table test1
( phone varchar(30),
id int )
insert into test1(phone,id) values('2345678',1)
insert into test1(phone,id) values('0562436720',1)
Create Procedure getStudentsByID
#ID
AS
BEGIN
declare #test varchar(max)
select #test = ISNULL(#test+',','')+ test1.phone from test1 where test1.id = #ID
select #test
This will return you the comma separated list of all the phone numbers of the given ID.

Suggestion for a tag cloud algorithm

I have a MSSQL 2005 table:
[Companies](
[CompanyID] [int] IDENTITY(1,1) NOT NULL,
[Title] [nvarchar](128),
[Description] [nvarchar](256),
[Keywords] [nvarchar](256)
)
I want to generate a tag cloud for this companies. But I've saved all keywords in one column separated by commas. Any suggestions for how to generate tag cloud by most used keywords. There could be millions of companies approx ten keywords per company.
Thank you.
Step 1: separate the keywords into a proper relation (table).
CREATE TABLE Keywords (KeywordID int IDENTITY(1,1) NOT NULL
, Keyword NVARCHAR(256)
, constraint KeywordsPK primary key (KeywordID)
, constraint KeywordsUnique unique (Keyword));
Step 2: Map the many-to-many relation between companies and tags into a separate table, like all many-to-many relations:
CREATE TABLE CompanyKeywords (
CompanyID int not null
, KeywordID int not null
, constraint CompanyKeywords primary key (KeywordID, CompanyID)
, constraint CompanyKeyword_FK_Companies
foreign key (CompanyID)
references Companies(CompanyID)
, constraint CompanyKeyword_FK_Keywords
foreign key (KeywordID)
references Keywords (KeywordID));
Step 3: Use a simple GROUP BY query to generate the 'cloud' (by example taking the 'cloud' to mean the most common 100 tags):
with cte as (
SELECT TOP 100 KeywordID, count(*) as Count
FROM CompanyKeywords
group by KeywordID
order by count(*) desc)
select k.Keyword, c.Count
from cte c
join Keyword k on c.KeywordID = k.KeywordID;
Step 4: cache the result as it changes seldom and it computes expensively.
I'd much rather see your design normalized as suggested by Remus, but if you're at a point where you can't change your design...
You can use a parsing function (the example I'll use is taken from here), to parse your keywords and count them.
CREATE FUNCTION [dbo].[fnParseStringTSQL] (#string NVARCHAR(MAX),#separator NCHAR(1))
RETURNS #parsedString TABLE (string NVARCHAR(MAX))
AS
BEGIN
DECLARE #position int
SET #position = 1
SET #string = #string + #separator
WHILE charindex(#separator,#string,#position) <> 0
BEGIN
INSERT into #parsedString
SELECT substring(#string, #position, charindex(#separator,#string,#position) - #position)
SET #position = charindex(#separator,#string,#position) + 1
END
RETURN
END
go
create table MyTest (
id int identity,
keywords nvarchar(256)
)
insert into MyTest
(keywords)
select 'sql server,oracle,db2'
union
select 'sql server,oracle'
union
select 'sql server'
select k.string, COUNT(*) as count
from MyTest mt
cross apply dbo.fnParseStringTSQL(mt.keywords,',') k
group by k.string
order by count desc
drop function dbo.fnParseStringTSQL
drop table MyTest
Both Remus and Joe are correct but yes as what Joe said if you dont have a choice then you have to live with it. I think I can offer you an easy solution by using an XML Data Type. You can already easily view the parsed column by doing this query
WITH myCommonTblExp AS (
SELECT CompanyID,
CAST('<I>' + REPLACE(Keywords, ',', '</I><I>') + '</I>' AS XML) AS Keywords
FROM Companies
)
SELECT CompanyID, RTRIM(LTRIM(ExtractedCompanyCode.X.value('.', 'VARCHAR(256)'))) AS Keywords
FROM myCommonTblExp
CROSS APPLY Keywords.nodes('//I') ExtractedCompanyCode(X)
now knowing that you can do that, all you have to do is to group them and count, but you cannot group XML methods so my suggestion is create a view of the query above
CREATE VIEW [dbo].[DissectedKeywords]
AS
WITH myCommonTblExp AS (
SELECT
CAST('<I>' + REPLACE(Keywords, ',', '</I><I>') + '</I>' AS XML) AS Keywords
FROM Companies
)
SELECT RTRIM(LTRIM(ExtractedCompanyCode.X.value('.', 'VARCHAR(256)'))) AS Keywords
FROM myCommonTblExp
CROSS APPLY Keywords.nodes('//I') ExtractedCompanyCode(X)
GO
and perform your count on that view
SELECT Keywords, COUNT(*) AS KeyWordCount FROM DissectedKeywords
GROUP BY Keywords
ORDER BY Keywords
Anyways here is the full article -->http://anyrest.wordpress.com/2010/08/13/converting-parsing-delimited-string-column-in-sql-to-rows/

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