I have a table name Students having (studentId, StudentName,Address,PhoneNo)
i have provided a filter for user to select only StudentId from Combobox to get the details of Students... and generate Report.
I have written following Query to get student Detail :
(select * from Students where StudentId = stdId)
Here stdId is a Parameter that i pass from code
It works fine if i select single studentId.... But in user selection Comobobox i have also provided "ALL" if user Select All from combobox i want to display details of all student
So what should I pass in stdId if user selects All ?
I used inline Query in C# (not using SQL Stored Procedure)
You can do it like this .
SELECT * from Students s
WHERE s.studentId = ISNULL(#StudentId,s.studentId)
When "All" is selected in combo box pass null in your #studentid parameter. If you can not pass null in parameter then pass -1 or anything which can not be contain in you combox option and do it like this:(if -1= All)
SELECT * from Students s
WHERE s.studentId = #StudentId or #StudentId=-1
You can also try the answer given by Curt.
If user selects all, pass NULL to #StudentId and change your query to:
select *
from Students
where (StudentId=#StudentId OR #StudentId IS NULL)
In your stored procedure header, change the definition of #StudentId so that it can be passed as NULL.
ALTER PROCEDURE dbo.WhateverYourProcedureIsCalled( #StudentId int = null )
Then change your WHERE clause as follows
...
SELECT * from Students
WHERE #StudentId IS NULL OR StudentId = #StudentId
From your code, if ALL is passed, you can omit the part where you set the value of the #StudentId parameter. SQL Server will use the default if not passed.
If the where clause is included in the query you also need to supply a valid parameter value and it is therefore not possible to get all students when the where clause is included.
You need to differentiate your query based on the value selected in the combobox. You can do something like the following.
int studentId = 0;
//Where selectedValue comes from your combobox
Int32.TryParse(selectedValue, out studentId);
var query = "select * from Students";
if (studentId > 0)
{
query = query + " where StudentId = #StudentId";
//Remember to add studentId as parameter value
}
Related
I use Npqsql 5. Is there any way to retrieve values for many different arguments using a single select?
For example I want to run:
"select value from table where id=#id1"
"select value from table where id=#id4"
"select value from table where id=#id12"
but as a single query in order to optimize.
Couple of options that come to mind:
select value from table where id = #id1 or id = #id4 or id = #id12
or
select value from table where id in (#id1, #id4, #id12)
I am using the table type as my input parameter in my stored procedure and I am passing in a list of comma separated Catalog Ids from my C# application.
But there is also an option on the web page where users can select 'All Catalog Ids' on the multi-select Catalog drop down.
What is the best 'short hand' way to write the query? Like, If I have a varchar variable as my input variable, then I would have written
SELECT [FIELD1], [FIELD2] FROM CATALOG WHERE (**#VarcharVariable is NULL** or CatalogName = #VarcharVariable ) for example.
But I am struggling to get that kind of 'short hand' notation on the WHERE clause, with this table type input parameter, as Table type parameter cannot be NULL.
I don't want to write a bunch of IF clauses, as I have 4 input parameters of list type that I am sending to this proc and Catalog ID is just one of them. I just want to JOIN the values in these input parameters with my base tables and send the output with a concise single query. Unfortunately any of these 4 table type input parameters can have 'All' as its value. If ALL, I just have to get everything of that entity.
I want to join these input parameters with my base tables ONLY if they have valid ids in the table and does not have 'All' equivalent.
Thanks
I used a bit variable. Here IDList is a user-defined type that I have created. If we see the WHERE condition below, I used the OR condition to keep it to one concise query but yet join bunch of base tables based on these list type (comma delimited string of IDs) of input parameters.
When I have to pass ALL from my c# app, I literally null the datatable input parameter out, so that these bit variables will have a value of 0 and the query pulls in all records for that entity..
CREATE PROC dbo.MyProc
(
#CatelogIDs IDList READONLY,
#TaskIDs IDList READONLY,
#SomeOtherIDs IDList READONLY
)
AS
BEGIN
DECLARE #bCatIDs bit=0
DECLARE #bTaskIDs bit=0
DECLARE #bSomeOtherIDs bit=0
IF EXISTS (SELECT 1 FROM #CatelogIDs)
BEGIN
SET #bCatIDs =1
END
IF EXISTS (SELECT 1 FROM #TaskIDs)
BEGIN
SET #bTaskIDs =1
END
IF EXISTS (SELECT 1 FROM #SomeOtherIDs)
BEGIN
SET #bSomeOtherIDs =1
END
SELECT col1, col2,col3
FROM [dbo].[MainTable] r
JOIN [dbo].Catalogs c ON c.ID = r.CatalogID
JOIN [dbo].[Tasks] t ON t.ID = r.TaskId
JOIN [dbo].[SomeotherTable] s ON s.ID = r.SomeotherID
WHERE (#bCatIDs = 0 OR r.CatalogID in (SELECT IDs FROM #CatelogIDs))AND
(#bTaskIDs = 0 OR r.TaskID in (SELECT IDs FROM #TaskIDs)) AND
(#bSomeOtherIDs = 0 OR r.SomeotherID in (SELECT IDs FROM #bSomeOtherIDs))
I'm creating a product search where users can search base of what they want or simply choose Any which means it will display all product.
since I'm searching based on what is in the dropdownList control, if user choose a product category i have query the database to display the product in that category. How can i query the database to display product in all category when the user select 'Any' from the dropdownList.
When you prepare your query include a IF
This is pseudo code, because Im not sure how you store the values in the combo or how you make your sql consult. So is just to give you the general idea.
if( dropdwonList.SelectedItem.Value == "any" ) {
select * from products ;
}
else {
select * from products where categoryID = dropdwonList.SelectedItem.Value;
}
Or use this query
SELECT *
FROM products
WHERE
( categoryID = ddCategory.SelectedItem.Value
OR ddCategory.SelectedItem.Value= -1 // `-1` is your ID for `ANY`
) AND
( modelID = ddModel.SelectedItem.Value
OR ddModel.SelectedItem.Value= -1
) AND ....
I have a products table and each product have a category field (this is not up to me to change and I need to read the data from it as it is), from the product table I wanted to update a category table with unique categories only (I also use a IFNULL to deal with empty categories), this is what I have so far that works:
string query = "INSERT INTO categories (name)
SELECT DISTINCT(IFNULL(category, \"Uncategorized\")) AS category_name
FROM products
WHERE NOT EXISTS (
SELECT name FROM categories
WHERE name = category_name)";
With the above query I am able to update the categories with unique category fields and every time I need to run it, it will add only categories that does not exist to the table.
But besides the above I also need to include a profile id with each category inserted something like this, which does not work:
string query = "INSERT INTO categories (profile_id, name)
SELECT " + profileId.ToString() + ",
DISTINCT(IFNULL(category, \"Uncategorized\")) AS category_name
FROM products
WHERE NOT EXISTS (
SELECT name FROM categories
WHERE name = category_name
AND profile_id = #profileId)";
Is there a way I could acomplish this with a query ?
The above gives me a message:
SQLite error near "DISTINCT": syntax error
SqliteMan error:
Query Error: near "DISTINCT": syntax error Unable to execute statement
Let me know if I havent been clear and what should I be more clear about.
You are using the DISTINCT keyword incorrectly: it is not a function. Try instead:
"INSERT INTO categories (profile_id, name)
SELECT DISTINCT '"+profileId.ToString()+"', IFNULL(category, 'Uncategorized')
FROM products
WHERE category_name NOT IN (
SELECT name FROM categories WHERE profile_id = "'+profileId.ToString()+"'
)
"
One assumes that profileId.ToString() is guaranteed to be safe from SQL injection, or else you would be escaping it/passing it as a parameter to a prepared statement?
i am trying to insert a statement contains WHERE from two different tables :
the table i want to insert into is dbo.order
the other two tables are :
dbo.users. user_id.
dbo.packages. package_id.
another order field "notes".
the statement i tried is
insert into dbo.order
(customer_id,package_id,notes)
Select user_id,Package_ID
from
dbo.users,dbo.packages
where
username = 'bader' AND package_name = 'beginner','notes value here';
any suggestions ?
There's no obvious join here so you'll get the cartesian product of Bader orders and beginner packages. Not sure what the notes value should be. If its a literal you can just include it in the select clause.
insert into dbo.order
(customer_id,package_id,notes)
Select
user_id,Package_ID , 'notes value here'
from
dbo.users,dbo.packages
where
username = 'bader' AND package_name = 'beginner';
insert into dbo.order
(customer_id,package_id,notes)
Select user_id, Package_ID, 'notes value here'
from
dbo.users, dbo.packages
where
username = 'bader' AND package_name = 'beginner';