SQL: datetime as a variable [closed] - sql

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Closed 10 years ago.
Trying to using parts of datetime as a variable in a procedure, so a parameter would be a month like 'June'. Here's what I wrote
/* 3. Create a stored procedure called sp_product_listing listing a specified product ordered during a specified month and year. The product and the month and year will be input parameters for the stored procedure. Display the product name, unit price, and quantity in stock from the products table, and the supplier name from the suppliers table. Run the stored procedure displaying a product name containing Jack and the month of the order date is June and the year is 2001. The stored procedure should produce the result set listed below.*/
CREATE PROCEDURE sp_product_listing
(
#product varchar(40),
#month datetime,
#year datetime
)
AS
SELECT
'product_name'=products.name,
'unit_price'=products.unit_price,
'quantity_in_stock'=products.quantity_in_stock,
'supplier_name'=suppliers.name
FROM
products
INNER JOIN suppliers ON suppliers.supplier_id=products.supplier_id
INNER JOIN order_details ON order_details.product_id=products.product_id
INNER JOIN orders ON orders.order_id=order_details.order_id
WHERE
products.name LIKE '%#product%' AND MONTH(orders.order_date) = #month AND YEAR(orders.order_date) = #year;
GO
/*Execute procedure*/
EXECUTE sp_product_listing 'Jack','June','2001'
Procedure is tested working fine until I add the variables, then it goes to H trying to convert varchar to datetime?
I've tried things like #month MONTH(datetime), etc. Not sure how to approach this? Maybe that's not even the problem?

Answer 1

You should not make "#month" datetime because, as its nametype implies, it expects data on the form "date and time" like YYYY/MM/DD hh:mm:ss, and "June" does not fits on the pattern I just presented. If you want just make one column for dates, let's call it [dateofsomething], then, you can pass a parameter "#date" (with type datetime) with a value like a normal date.
Of course, if you want the current date, just use getdate()
Good luck

Answer 2

This should work
CREATE PROCEDURE sp_product_listing
(
#product varchar(40),
#month int,
#year int
)
AS
SELECT
'product_name'=products.name,
'unit_price'=products.unit_price,
'quantity_in_stock'=products.quantity_in_stock,
'supplier_name'=suppliers.name
FROM
products
INNER JOIN suppliers ON suppliers.supplier_id=products.supplier_id
INNER JOIN order_details ON order_details.product_id=products.product_id
INNER JOIN orders ON orders.order_id=order_details.order_id
WHERE
products.name LIKE '%#product%' AND MONTH(orders.order_date) = #month AND YEAR(orders.order_date) = #year;
GO
/*Execute procedure*/
EXECUTE sp_product_listing 'Jack',6,2001

Answer 3

June is not a DateTime value, nor is 2001. Try passing in a complete Date as a single value, then adding a month to determine the search window:
EDIT: Updated sample code.
-- Pass the month and year as a string and an integer.
declare #Month as VarChar(16)
declare #Year as Int
set #Month = 'June'
set #Year = 2001
-- Combine them into a date representing the first day of the desired month and year.
declare #WindowStart as Date = Cast( '1 ' + #Month + Cast( #Year as VarChar(4) ) as Date )
-- Calculate the start of the following month.
declare #WindowEnd as Date = DateAdd( month, 1, #WindowStart )
-- Display the resulting window of dates.
select #WindowStart as WindowStart, #WindowEnd as WindowEnd
Compare using: #WindowStart <= orders.order_date and orders.order_date < #WindowEnd
That will allow the optimizer to use an index on order_date. The importance of this may become apparent later in the term.