SQL左联接-右表中的多行

Question

I am trying to make PHP / MySQL Search Form. When a user wants to search he need to fill 3 input fields: FromDate , ToDate and SucategoryID .

There are 2 tables: Items and ItemsBlockDates In Table Items, there is info about the item and it is identified by ID. In Table ItemBlockDates, there is info about a period when Item will not be displayed in search results. It contains: ItemID, FromDate , and Date fields. Also, there is a possibility to define more than one Block Date for one item.

Now, I want to select all Items where FromDate and To Date inputs does not match with any of rows in ItemsBlockDates with same ItemID.

I wrote a query, but there is a problem:

SELECT * 
FROM Items 
LEFT JOIN ItemBlockDates ON Items.ID = ItemBlockDates.ItemID 
WHERE Items.SubcategoryID = :SubcategoryID   
  AND ItemBlockDates.FromDate NOT BETWEEN CAST(:FromDate AS DATETIME) AND CAST(:ToDate AS DATETIME)

When I run this query it does not display Items where Block Dates are not set, also it displays items where more than one Block Date is set.

Answer 1

I want to select all Items where FromDate and To Date inputs does not match with any of rows in ItemsBlockDates with same ItemID.

To me, this suggests NOT EXISTS :

SELECT i.* 
FROM Items i
WHERE i.SubcategoryID = :SubcategoryID AND
      NOT EXISTS (SELECT 1
                  FROM ItemBlockDates ibd
                  WHERE i.ID = ibd.ItemID AND
                        ibd.FromDate BETWEEN CAST(:FromDate AS DATETIME) AND CAST(:ToDate AS DATETIME)
                 );

If you are passing in a parameter, I'm not sure why you need to convert to a DATETIME . You should be able to pass it in with the correct type.