SQL Switch/Case in 'where' clause with and

Question

I currently have this query

DECLARE @user uniqueidentifier
, @day_to_find int
, @date DATETIME = getdate()

SELECT
    @user = CAST(Value AS uniqueidentifier)
FROM BookSoreConfiguration.dbo.Config(NOLOCK)
WHERE Key = 'SuperUser.Id'

SELECT
    @day_to_find = CAST(Value AS int)
FROM BookSoreConfiguration.dbo.Config(NOLOCK)
WHERE Key = 'Returns.MaxDay'

--INSERT INTO...... //Part not copied for cleaning

    SELECT DISTINCT
        @user,
        @date,
        bd.shopping_code,
        bd.cod_gender,
        bd.book_number,
        '03',
        '01',
        '11',
        @user,
        @user,
        GETDATE(),
        GETDATE(),
        ean_code,
        15,
        bd.cod_variation,
    FROM bdo.BOOK_DATA bd WITH (NOLOCK)
-- various inner joins...
    WHERE 
    btw.num_catalog IS NOT NULL
    AND(
        (
        AND DATEDIFF(DAY, btw.sell_date, GETDATE()) >= @day_to_find
        OR (cod_catalog = '04'
        AND bd.cod_category NOT IN ('children', 'used', 'discounted'))
    AND bd.cod_state= '00'
    AND bd.cod_variation = '00'
    AND NOT EXISTS (SELECT TOP 1
        *
    FROM BOOK_RETURNS br (NOLOCK)
    WHERE br.code = bd.shopping_code
    AND br.cod_category = bd.cod_category
    AND br.book_number = bd.book_number
    AND br.cod_request_returns = 1
    AND br.num_progr_bd = bd.prog
    AND br.cod_elaboration = '103')
GO

I need to modify this part:

AND DATEDIFF(DAY, btw.sell_date, GETDATE()) >= @day_to_find

If bd.shopping_code is "B41", "B74", "BT34" the and must become

AND DATEDIFF(DAY, btw.sell_date, GETDATE()) >= 30

In all other cases the and will remain

AND DATEDIFF(DAY, btw.sell_date, GETDATE()) >= @day_to_find

Is it possible to manage the two cases through the switch case or are there other possible ways?

EDIT 2022/05/13 What if I used a UNION?

DECLARE @user uniqueidentifier
, @day_to_find int
, @date DATETIME = getdate()

SELECT
    @user = CAST(Value AS uniqueidentifier)
FROM BookSoreConfiguration.dbo.Config(NOLOCK)
WHERE Key = 'SuperUser.Id'

SELECT
    @day_to_find = CAST(Value AS int)
FROM BookSoreConfiguration.dbo.Config(NOLOCK)
WHERE Key = 'Returns.MaxDay'

--INSERT INTO...... //Part not copied for cleaning

    SELECT DISTINCT
        @user,
        @date,
        bd.shopping_code,
        bd.cod_gender,
        bd.book_number,
        '03',
        '01',
        '11',
        @user,
        @user,
        GETDATE(),
        GETDATE(),
        ean_code,
        15,
        bd.cod_variation,
    FROM bdo.BOOK_DATA bd WITH (NOLOCK)
-- various inner joins...
    WHERE
    bd.shopping_code NOT IN ('B41', 'B74', 'BT34')
    AND btw.num_catalog IS NOT NULL
    AND(
        (
        AND DATEDIFF(DAY, btw.sell_date, GETDATE()) >= @day_to_find
        OR (cod_catalog = '04'
        AND bd.cod_category NOT IN ('children', 'used', 'discounted'))
    AND bd.cod_state= '00'
    AND bd.cod_variation = '00'
    AND NOT EXISTS (SELECT TOP 1
        *
    FROM BOOK_RETURNS br (NOLOCK)
    WHERE br.code = bd.shopping_code
    AND br.cod_category = bd.cod_category
    AND br.book_number = bd.book_number
    AND br.cod_request_returns = 1
    AND br.num_progr_bd = bd.prog
    AND br.cod_elaboration = '103')
    
    UNION
    SELECT DISTINCT
        @user,
        @date,
        bd.shopping_code,
        bd.cod_gender,
        bd.book_number,
        '03',
        '01',
        '11',
        @user,
        @user,
        GETDATE(),
        GETDATE(),
        ean_code,
        15,
        bd.cod_variation,
    FROM bdo.BOOK_DATA bd WITH (NOLOCK)
-- various inner joins...
    WHERE
    bd.shopping_code IN ('B41', 'B74', 'BT34')
    AND btw.num_catalog IS NOT NULL
    AND(
        (
        AND DATEDIFF(DAY, btw.sell_date, GETDATE()) >= 30
        OR (cod_catalog = '04'
        AND bd.cod_category NOT IN ('children', 'used', 'discounted'))
    AND bd.cod_state= '00'
    AND bd.cod_variation = '00'
    AND NOT EXISTS (SELECT TOP 1
        *
    FROM BOOK_RETURNS br (NOLOCK)
    WHERE br.code = bd.shopping_code
    AND br.cod_category = bd.cod_category
    AND br.book_number = bd.book_number
    AND br.cod_request_returns = 1
    AND br.num_progr_bd = bd.prog
    AND br.cod_elaboration = '103')
GO

Answer 1

Since the left part remains the same and only the value can be different, you could try the following approach (CASE 'returns' the value of the right part):

AND DATEDIFF(DAY, btw.sell_date, GETDATE()) >= 
  CASE
    WHEN bd.shopping_code IN ('B41', 'B74', 'BT34') THEN 30
    ELSE @day_to_find
  END

Answer 2

WHERE
    (
        bd.shopping_code IN ('B41', 'B74', 'BT34') AND DATEDIFF(DAY, btw.sell_date, GETDATE()) >= 30
        OR
        DATEDIFF(DAY, btw.sell_date, GETDATE()) >= @day_to_find
     )
     AND ...