Develop Reference

How can I reuse subquery in condition checking in SQL Server?

I want to retrieve the results from SQL Server 2012.But for checking condition I rewrote the same subquery.Is there any idea to use the subquery just once and retrieve the result?
My query:
sql = "SELECT customer_id,ISNULL(first_name, '') + ' ' + ISNULL(middle_name, ' ') + ' ' + ISNULL(last_name, ' ') AS 'Customer_name', (ISNULL(city, '') + ',' + ISNULL(district, ' ') + ',' + ISNULL(zone, ' ')) as 'Location' FROM customer_detail WHERE 1=1";
if(location != "")
{
sql += " AND (ISNULL(city, '') + ',' + ISNULL(district, ' ') + ',' + ISNULL(zone, ' ')) LIKE '%" + location + "%'"";
}
Query after AND is same as above subquery. Thanks in advance.

It seems you are not looking so much for sub-query than a user defined function (UDF) to merge 3 text column in a prettier way.
If you do not want to use UDF then you could use Common Table Expressions (CTE) to write the expression just once.
Using CTE has also the benefit of encapsulating your reused block right inside query, whereas the UDF would need to be added to your DB before executing your query. This may or may not be a desirable thing depending on reusability needs.
CTE solution would be along the lines of this:
WITH CTE (Id, [Name], [Location]) as
(
SELECT customer_id,
ISNULL(first_name, '') + ' ' + ISNULL(middle_name, ' ') + ' ' + ISNULL(last_name, ' '),
ISNULL(city, '') + ',' + ISNULL(district, ' ') + ',' +ISNULL(zone, ' ')
FROM customer_detail
)
select *
from CTE
where 1=1
AND [Location] LIKE '%' + #location + '%'
Also, generally you can expect CTE to perform generally better than UDFs as the query optimizer can modify the plan to match specific query needs.

I would go with a reusable view and stored procedure for the actual search.
create view vCustomerDetail
as
select [customer_id]
, isnull([first_name] + ' ', '') + isnull([middle_name] + ' ', '') + isnull([last_name], '') as [Customer_name]
, isnull([city] + ', ', '') + isnull([district] + ', ', '') + isnull([zone], '') as [Location]
from [customer_detail]
go
create proc pCustomerDetailByLocation
(
#location nvarchar(200) = ''
)
as
begin
set nocount on;
select *
from [vCustomerDetail]
where [Location] = ''
union all
select *
from [vCustomerDetail]
where [Location] like '%' + #location + '%';
end
go
You would call the stored procedure from your code with and pass along the location in the parameter. That way you can prevent SQL injection and also make use of better execution plan caching than with an ad-hoc query.
You can either use a union like I've done in my example, or combine it with an OR statement, like so:
where [Location] = '' or [Location] like '%' + #location + '%';
I found the union to be beneficial in some cases over because you're helping the optimizer split up his lookup logic.

Joining across several tables - then applying a PIVOT to display the data differently

I am trying to figure a way to execute a seemingly complex join scenario, and am unsure as to how to go about it.
Some Background info:
-I have a 'ProjectCategory' table, which contains a foreign key 'ProjectID' and 'CategoryID' to the Project and Category tables respectively. One project could have as many assigned categories to it as there are existing (up to 10)
-I have a 'Budget' table and a 'Sponsor' Table.
-My 'Project' table is related to my 'Budget' Table in that all Projects have an associated BudgetID
-My 'Budget' Table is related to my 'Sponser' table in that all Budgets have an associated SponsorID.
-'Project' table and 'Sponsor' table are not directly related.
An example of the result set that I am trying to get is firstly:
SponsorName(Field in sponsor table) - ProjectName - Category
___________________________________ ___________ ________
A ABC categoryA
A ABC categoryB
A DEF categoryX
A DEF categoryZ
I would then like to use a PIVOT to show the data like:
SponsorName - ProjectName -categoryA - categoryB -categoryC - categoryD ...
___________ ___________ _________ _________ _________ _________
A ABC X X
A DEF X X
B EFG X X
Where the Xs mark which categories are associated with each project/sponsor combination. The filling in of the Xs is maybe something I will do in the codebehind or using other stored procedures, but this is the basic idea of what I am trying to do.
I am having trouble even figuring out how to write a query to get back the first set before I even implement a pivot to show it as the second set, so I am a bit intimidated by this task. Any help greatly appreciated, and please let me know if you need any more information

Assuming SQL Server, I use a stored procedure for the bulk of Dynamic PIVOTS. (Listed Below)
The source could be a table, #temp or even SQL
Exec [prc-Pivot] '#Temp','Category','max(''X'')[]','SponsorName,ProjectName',null
Returns
SponsorName ProjectName categoryA categoryB categoryD categoryX categoryZ
A ABC X X NULL NULL NULL
A DEF NULL NULL NULL X X
B EFG X NULL X NULL NULL
The Stored Procedure
CREATE PROCEDURE [dbo].[prc-Pivot] (
#Source varchar(1000), -- Any Table or Select Statement
#PvotCol varchar(250), -- Field name or expression ie. Month(Date)
#Summaries varchar(250), -- aggfunction(aggValue)[optionalTitle]
#GroupBy varchar(250), -- Optional additional Group By
#OtherCols varchar(500) ) -- Optional Group By or aggregates
AS
--Exec [prc-Pivot] 'Select Year=Year(TR_Date),* From [Chinrus-Series].[dbo].[DS_Treasury_Rates]','''Q''+DateName(QQ,TR_Date)','avg(TR_Y10)[-Avg]','Year','count(*)[Records],min(TR_Y10)[Min],max(TR_Y10)[Max],Avg(TR_Y10)[Avg]'
Set NoCount On
Set Ansi_Warnings Off
Declare #Vals varchar(max),#SQL varchar(max);
Set #Vals = ''
Set #OtherCols= IsNull(', ' + #OtherCols,'')
Set #Source = case when #Source Like 'Select%' then #Source else 'Select * From '+#Source end
Create Table #TempPvot (Pvot varchar(100))
Insert Into #TempPvot
Exec ('Select Distinct Convert(varchar(100),' + #PvotCol + ') as Pvot FROM (' + #Source + ') A')
Select #Vals = #Vals + ', isnull(' + Replace(Replace(#Summaries,'(','(CASE WHEN ' + #PvotCol + '=''' + Pvot + ''' THEN '),')[', ' END),NULL) As [' + Pvot ) From #TempPvot Order by Pvot
Drop Table #TempPvot
Set #SQL = Replace('Select ' + Isnull(#GroupBy,'') + #OtherCols + #Vals + ' From (' + #Source + ') PvtFinal ' + case when Isnull(#GroupBy,'')<>'' then 'Group By ' + #GroupBy + ' Order by ' + #GroupBy else '' end,'Select , ','Select ')
--Print #SQL
Exec (#SQL)
Set NoCount Off
Set Ansi_Warnings on

Entity Framework Conditional Left Join and Custom Column Select

I have a stored procedure which results in lots of data. and also want to convert this to EF
unable to figure out how to join to the relavent tables when an attribute is present for the system. and also the column selection is very dynamic in nature,
I could take this sql and execute this directly and get things sorted that way but would miss but the grid in the front end wont be able to handle 600mb of data thrown from the database.
so need paging thought can do this better with EF.
for reference purpose I have the following sql below.
Declare #SQL varchar(max);
Declare #SelectColumns VARCHAR(MAX)
SELECT DISTINCT #SelectColumns= STUFF((SELECT ',''' + [PrimaryDataSource] + ''' Golden'
+ ISNULL(CASE WHEN System1 IS NOT NULL THEN ', System1.' + QUOTENAME([System1]) + ' System1' END, '')
+ ISNULL(CASE WHEN System2 IS NOT NULL THEN ', System2.' + QUOTENAME([System2]) + ' System2' END, '')
+ ISNULL(CASE WHEN [System3] IS NOT NULL THEN ', System3.' + QUOTENAME([System3])+ ' System3' END, '')
+ ISNULL(CASE WHEN System4 IS NOT NULL THEN ', System4.' + QUOTENAME(System4)+ ' System4' END, '')
+ ISNULL(CASE WHEN System5 IS NOT NULL THEN ', System5.' + QUOTENAME(System5)+ ' System5' END, '')
+ ISNULL(CASE WHEN System6 IS NOT NULL THEN ', System6.' + QUOTENAME(System6)+ ' System6' END, '')
FROM [dbo].[TBL_Mapping]
where Attribute =#attributeName
FOR XML PATH(''), TYPE
).value('.', 'VARCHAR(MAX)')
,1,1,'')
SET #SQL = '
SELECT distinct
m.ID MappingID,
m.KeyValueUniqueKey,
m.ValueKeyUniqueKey,
' + #SelectColumns + '
FROM [dbo].[TBL_Mapping] M '
IF CHARINDEX('System1.',#SelectColumns) > 0
BEGIN
SET #SQL = #SQL +
'
LEFT OUTER JOIN dbo.VW_System1_ALL System1 ON
System1.System1ID=M.System1ID '
END
IF CHARINDEX('System2.',#SelectColumns) > 0
BEGIN
SET #SQL = #SQL +
'
LEFT OUTER JOIN dbo.TBL_System2 System2 ON
M.System2ID= System2.System2ID '
END
IF CHARINDEX('System4.',#SelectColumns) > 0
BEGIN
SET #SQL = #SQL + '
LEFT OUTER JOIN DBO.tbl_System4 System4 ON
System4.Key1 = M.KeyValueUniqueKey AND
System4.Value1 = ValueKeyUniqueKey '
END
IF CHARINDEX('System5.',#SelectColumns) > 0
BEGIN
SET #SQL = #SQL + '
LEFT OUTER JOIN DBO.tbl_System5 System5 ON
System5.System5Id = M.System5Id'
END
IF CHARINDEX('System6.',#SelectColumns) > 0
BEGIN
SET #SQL = #SQL + '
LEFT OUTER JOIN dbo.tbl_system6 System6 ON
System6.System6Id = M.System6Id'
END
IF CHARINDEX('System3.',#SelectColumns) > 0
BEGIN
SET #SQL = #SQL + '
LEFT OUTER JOIN [dbo].[TBL_System3] System3 ON
System3.System3Id = M.System3Id'
END
SET #SQL = #SQL + '
WHERE m.version=0 and isActive=1
ORDER by m.ID'
print #SQL
exec (#SQL)
I have looked at the Leftjoin2 extn method but that is not helping much.
What is the best possible action to get this on to EF.
or EF itself is a wrong choise for this sort of problems?

You can do dynamic query generating and then in the end do Skip().Take().
Your model for custom object may look like this:
class MappingData
{
//not sure what the data types are.
int MappingId;
int KeyValueUniqueKey;
int ValueKeyUniqueKey;
string System1;
string System2;
...
string System6;
}
Then in the get method map data,
IQueryable<MappingData> sql = db.TBL_Mapping
.Select(m => new MappingData {
MappingId = ID,
KeyValueUniqueKey = KeyValueUniqueKey,
ValueKeyUniqueKey = ValueKeyUniqueKey,
//leave other columns out
//they will be filled in
//dynamically
})
.Distinct();//get distinct
//--------------------
//REPEAT START
bool HasSystem1 = db.TBL_Mapping.Any(m => m.System1 != null);
//left outer join with System1 if it has it in the TBL_Mapping
if (HasSystem1)
{
sql =
from m in sql
join s1 in db.VW_System1_ALL
on m.System1ID equals s1.System1ID into stemp
from st in stemp.DefaultIfEmpty()
select new { MappingId = st.Id,
KeyValueUniqueKey = st.KeyValueUniqueKey,
ValueKeyUniqueKey = st.ValueKeyUniqueKey,
System1 = st.System1 }; //SystemX column.
}
//REPEAT END
//--------------------
// repeat the above for System2 thru System6
//And in the end do paging.
var result = sql
.Skip(currentPageNumber * numberOfObjectsInPage)
.Take(numberOfObjectsInPage);

This is a bad fit for EF. If all you are only trying to add paging -- add your own paging functionality to the stored proc. You can do this by using ROW_NUMBER OVER what every you are sorting by, then use an an outer query to return the page of data you want, for example...
CREATE PROCEDURE [dbo].[PagedSomething]
#pageSize int,
#pageNum int -- assume pages are 0-based
AS
BEGIN
-- outer query does the paging in its where clause,
-- returning the selected "pages" from the raw results of the inner query
SELECT RawResults.SomethingId
FROM
-- inner query where you make your basic data
(SELECT
s.SomethingId
, ROW_NUMBER() OVER(ORDER BY s.SomethingId) RowID
FROM Somethings s) RawResults
WHERE RowID >= #pageNum * #pageSize + 1
AND RowID < (#pageNum + 1) * #pageSize + 1
END

Sql server select - varchar containing column name and value

I need to add a bunch of c# code to test values against a table. Connecting directly to the data source is out of the question (this needs to be static code).
The output is
X.AddColumn("ColumnName",ColumnValue);
I would like to get a SQL statement that, for a table returns the above pattern, listing each column of a row, iterating through every row in the table.
I was hoping for a select statement in the db that I could copy and paste result set of, ideally one that went through columns dynamically to save me doing something like below for each table I wish to output.
SELECT 'X.AddColumn("ColumnName1", ' + CONVERT(VARCHAR, ColumnName1, 100) +');' AS Col1
...
'X.AddColumn("ColumnNameN", ' + CONVERT(VARCHAR, ColumnNameN, 100) +');' AS ColN
FROM
Schema.Table1

Of the top of my head, this is a 2 step process:
Run the statement below. It will create a query for each of the columns of your table (something like select 'x.AddColumn("Column1", ' + Convert(varchar, Column1, 100) +' )' from dbo.Table1)
SELECT 'select ''x.AddColumn("' + c.column_name
+ '", ''+ Convert(varchar, ' + c.column_name
+ ',100)+'' )'' from ' + c.table_schema + '.'
+ c.table_name
FROM information_schema.columns c
WHERE c.table_name = 'Table1'
AND c.table_schema = 'dbo'
Copy the output of the statement above and run it. It should give you the desired output.

SQL Server - PIVOT

We are working on a C# application, we've been using Linq to SQL or standard ADO (when performance needed) to work with SQL Server.
We have a table layed out like so:
Customer ID, Year/Month, Product Name, Quantity
Each customer has additional columns per product.
We need display this information in a data grid like so:
Customer, Year/Month, Product A Quantity, Product B Quantity, Product C Quantity, etc.
What query could give us these results? And how could it be dynamic no matter what products are added and removed? We will be using a ListView in WPF for displaying the data.
We would just store the information differently, but they can add/remove products all the time.
Will PIVOT work?
(PS - the product names are really in another table for normalization, I changed it a little for simplicity for you guys)

The sql pivot command can be used but it requires the columns to be hard-coded. You could either hard-code them, use dynamic sql to generate the columns, or only get the raw data from sql without a pivot and do the data massaging in c#.

You can use pivot with dynamic SQL. Following T-SQL code is taken from this article on sqlteam.com. I've tried to modify the sample for your needs. Also beware of dangers using dynamic SQL, it might lead to SQL Injection if a product name contains apostrophe.
Create a stored proc first;
CREATE PROCEDURE crosstab
#select varchar(8000),
#sumfunc varchar(100),
#pivot varchar(100),
#table varchar(100)
AS
DECLARE #sql varchar(8000), #delim varchar(1)
SET NOCOUNT ON
SET ANSI_WARNINGS OFF
EXEC ('SELECT ' + #pivot + ' AS pivot INTO ##pivot FROM ' + #table + ' WHERE 1=2')
EXEC ('INSERT INTO ##pivot SELECT DISTINCT ' + #pivot + ' FROM ' + #table + ' WHERE '
+ #pivot + ' Is Not Null')
SELECT #sql='', #sumfunc=stuff(#sumfunc, len(#sumfunc), 1, ' END)' )
SELECT #delim=CASE Sign( CharIndex('char', data_type)+CharIndex('date', data_type) )
WHEN 0 THEN '' ELSE '''' END
FROM tempdb.information_schema.columns
WHERE table_name='##pivot' AND column_name='pivot'
SELECT #sql=#sql + '''' + convert(varchar(100), pivot) + ''' = ' +
stuff(#sumfunc,charindex( '(', #sumfunc )+1, 0, ' CASE ' + #pivot + ' WHEN '
+ #delim + convert(varchar(100), pivot) + #delim + ' THEN ' ) + ', ' FROM ##pivot
DROP TABLE ##pivot
SELECT #sql=left(#sql, len(#sql)-1)
SELECT #select=stuff(#select, charindex(' FROM ', #select)+1, 0, ', ' + #sql + ' ')
EXEC (#select)
SET ANSI_WARNINGS ON
Then try the following (I haven't test it, you might need to add qty to select statement)
EXECUTE crosstab 'select ProductID,CustomerID, YearMonth from sales group by ProductId', 'sum(qty)','ProductId','sales'

If you want to try a method that doesn't involve dynamic SQL, you could go through C#.
This guy ran a test comparing the two: http://weblogs.sqlteam.com/jeffs/jeffs/archive/2005/05/12/5127.aspx