Fill a drop-down list parameter with specific available values - sql

Question

I have an SSRS report that creates report from a SQL table:
id type name
1 fruit wilk
2 fruit scot
3 paper jon
4 pen brad
5 tape lin
6 water james
The report has two data sets: one feeds query for report, and the other feeds data to parameter. So in the report the multi-value parameter gets its values from dataset2.
-- dataset1::
select ID, TYPE, name from table1 where type in (#types)
-- dataset2::
select TYPE from table1
The report is generated based on type selected from dropdown list (which is a multi select list).
For example if we select "fruit" the report displays:
wilk, scot
If we select "water":
james
Now the thing is that I need to create a name for all the values "TAPE", "pen", and "paper", say the name "STATIONARY", such that the dropdown list should show only:
fruit, stationary, water
And when I select "STATIONARY" from thedropdown list the report should display:
jon, brad, lin (all 3 have some form of stationary, i.e paper, pen, tape)
And when I select type as "STATIONARY" and "water" it should display:
jon, brad, lin, james

Answer 1

Just from the hip here.
Consider adding a category field to your table. So for your fruit and water you could have a category called "Food", and for your pen, paper, and tape the category would be called "stationary".
Add another dataset to your report called "category".
SELECT Category FROM table1
Add another parameter that is a multiple selection of your new data set called #Category.
In your main query add:
...AND Category IN (#Category)
EDIT
Keep in mind this advice completely ignores normalization in your database. I understand that is not the intent of your question but it is something you should always consider. If it were me I would even add a category table. Then with the "table1" as you call it I would add a foriegn key pointing at an ID in the category table. You can even see this issue with your type column. Notice how fruit is used more than once.

Answer 2

I'd create another couple of tables for this called Item and ItemType.
ItemType has two fields: ItemTypeId (the auto-incrementing primary key) and Name. ItemType will have values like:
ItemTypeId Name
1 Food
2 Stationery
Item has three fields: ItemId (the auto-incrementing primary key), Name and ItemTypeId (from the ItemType table above). It looks like this:
ItemId Name ItemTypeId
1 Fruit 1
2 Paper 2
3 Pen 2
4 Tape 2
5 Water 1
Add the ItemId field to table1 and remove the type field, so it now looks like:
id ItemId name
1 1 wilk
2 1 scot
3 2 jon
4 3 brad
5 4 lin
6 5 james
We now know the type of the item from the link to the ItemType.
Create two parameters: #ItemTypes and #Items as multi-value.
#ItemTypes populates from the ItemType table:
SELECT ItemTypeId, Name FROM ItemType
ItemTypeId is the Value and Name is the Label.
#Items populates from the Item table but is filtered on the #ItemTypes parameter like so:
SELECT ItemId, Name FROM Item WHERE (ItemTypeId IN #ItemTypes)
ItemId is the Value and Name is the Label.
Now when you select #ItemTypes in the first parameter, the second parameter will only show items of that type.
Okay, back to your query. Your main query now looks like:
SELECT Item.Name AS ItemName, ItemType.Name AS ItemTypeName, table1.Name
FROM table1
INNER JOIN Item ON Item.ItemId = table1.ItemId
INNER JOIN ItemType ON ItemType.ItemTypeId = Item.ItemTypeI
WHERE (ItemType.ItemTypeId IN #ItemTypes)
AND (Item.ItemId IN #Items)
and I think our work here is done.