SQL Server : error converting string to smalldatetime?

Question

Can anyone help me with the following extract of code I have put together. The error appears to be in the CASE statement but I'm unable to see where as all the code parts after THEN have been tested individually and work.

Also to note that all dates are in datetime data type being yyyy-mm-dd hh:mm:ss.sss

SELECT 
    TICKET_ID,
    CAL_CR.a_DayName,
    CREATED, 
    CAL_CL.a_DayName,
    CLOSED,
    CASE
        WHEN CAL_CR.A_DATE IN ('Saturday','Sunday') AND CLOSED IS NULL THEN (DATEDIFF(WEEKDAY,created, closed)*10*60 - (DATEDIFF(MINUTE,CURRENT_TIMESTAMP,CAST(CAST(CAST(CURRENT_TIMESTAMP AS DATE) AS VARCHAR) + ' 18:00' AS DATETIME))))
        WHEN CLOSED IS NULL THEN (DATEDIFF(WEEKDAY,created, closed)*10*60 - (DATEDIFF(MINUTE,CAST(CAST(CAST(CREATED AS DATE) AS VARCHAR) + ' 08:30' AS DATETIME),CREATED)) - (DATEDIFF(MINUTE,CURRENT_TIMESTAMP,CAST(CAST(CAST(CURRENT_TIMESTAMP AS DATE) AS VARCHAR) + ' 18:00' AS DATETIME))))
        WHEN CAL_CR.A_DATE IN ('Saturday','Sunday') AND CLOSED IS NOT NULL THEN (DATEDIFF(WEEKDAY,created, closed)*10*60 - (DATEDIFF(MINUTE,CLOSED,CAST(CAST(CAST(CLOSED AS DATE) AS VARCHAR) + ' 18:00' AS DATETIME))))
        WHEN CAL_CL.A_DATE IN ('Saturday','Sunday') AND CLOSED IS NOT NULL THEN (DATEDIFF(WEEKDAY,created, closed)*10*60 - (DATEDIFF(MINUTE,CAST(CAST(CAST(CREATED AS DATE) AS VARCHAR) + ' 08:30' AS DATETIME),CREATED)))
        WHEN (CAL_CR.A_DATE IN ('Saturday','Sunday')) AND (CAL_CL.A_DATE IN ('Saturday','Sunday')) AND CLOSED IS NOT NULL THEN (DATEDIFF(WEEKDAY,created, closed)*10*60)
        ELSE (DATEDIFF(WEEKDAY,created, closed)*10*60 - (DATEDIFF(MINUTE,CAST(CAST(CAST(CREATED AS DATE) AS VARCHAR) + ' 08:30' AS DATETIME),CREATED)) - (DATEDIFF(MINUTE,CLOSED,CAST(CAST(CAST(CLOSED AS DATE) AS VARCHAR) + ' 18:00' AS DATETIME))))
    END AS Open_Minutes
FROM 
    OST_TICKET 
LEFT JOIN
    AMI_STATIC.DBO.SB_CALENDAR CAL_CR
    ON
        CAL_CR.a_Date = CAST(CREATED AS DATE)
LEFT JOIN
    AMI_STATIC.DBO.SB_CALENDAR CAL_CL
    ON
        CAL_CL.a_Date = CAST(CLOSED AS DATE)

Many Thanks in advance for any help at all.

---

Thanks Dems,

Taken your suggestions and tidied the code up a little further. See Below:

SELECT 
    TICKET_ID,
    CAL_CR.a_DayName,
    CREATED, 
    CAL_CL.a_DayName,
    CLOSED,
    CASE
        WHEN CAL_CR.A_DATE IN ('Saturday','Sunday') AND CLOSED IS NULL THEN DATEDIFF(WEEKDAY,created, closed)*10*60 - DATEDIFF(MINUTE,CAST(CURRENT_TIMESTAMP AS TIME),CAST('18:00' AS TIME))
        WHEN CLOSED IS NULL THEN DATEDIFF(WEEKDAY,created, closed)*10*60 - DATEDIFF(MINUTE,CAST('08:30' AS TIME),CAST(CREATED AS TIME)) - DATEDIFF(MINUTE,CAST(CURRENT_TIMESTAMP AS TIME),CAST('18:00' AS TIME))
        WHEN CAL_CR.A_DATE IN ('Saturday','Sunday') AND CLOSED IS NOT NULL THEN DATEDIFF(WEEKDAY,created, closed)*10*60 - DATEDIFF(MINUTE,CAST(CLOSED AS TIME),CAST('18:00' AS TIME))
        WHEN CAL_CL.A_DATE IN ('Saturday','Sunday') AND CLOSED IS NOT NULL THEN DATEDIFF(WEEKDAY,created, closed)*10*60 - DATEDIFF(MINUTE,CAST('08:30' AS TIME),CAST(CREATED AS TIME))
        WHEN (CAL_CR.A_DATE IN ('Saturday','Sunday')) AND (CAL_CL.A_DATE IN ('Saturday','Sunday')) AND CLOSED IS NOT NULL THEN DATEDIFF(WEEKDAY,created, closed)*10*60
        ELSE DATEDIFF(WEEKDAY,created, closed)*10*60 - DATEDIFF(MINUTE,CAST('08:30' AS TIME),CAST(CREATED AS TIME)) - DATEDIFF(MINUTE,CAST(CLOSED AS TIME),CAST('18:00' AS TIME))
    END AS Open_Minutes
FROM 
    OST_TICKET 
LEFT JOIN
    AMI_STATIC.DBO.SB_CALENDAR CAL_CR
    ON
        CAL_CR.a_Date = CAST(CREATED AS DATE)
LEFT JOIN
    AMI_STATIC.DBO.SB_CALENDAR CAL_CL
    ON
        CAL_CL.a_Date = CAST(CLOSED AS DATE)

Still getting the same error though:

Conversion failed when converting character string to smalldatetime data type.

Which is starting to get a little annoying.

Taking the code apart still works as well

SELECT 
    DATEDIFF(WEEKDAY,created, closed)*10*60 - DATEDIFF(MINUTE,CAST('08:30' AS TIME),CAST(CREATED AS TIME)) - DATEDIFF(MINUTE,CAST(CLOSED AS TIME),CAST('18:00' AS TIME))
FROM 
    OST_TICKET
WHERE 
    TICKET_ID = 30374

Thanks,

Marcus

Answer 1

You're casting DATETIMEs to VARCHAR and then back to DATETIMEs, such as here...
- CAST(CAST(CAST(CURRENT_TIMESTAMP AS DATE) AS VARCHAR) + ' 18:00' AS DATETIME)

At the very least you need to specify a size; VARCHAR(16) rather than just VARCHAR. If you don't, you're actually only getting a maximum of 1 character.

But, also, if you're casting dates and times to strings to manipulate them, you're almost always doing something 'wrong'. I'd recommend something more like...
- DATEADD(hour, 18, CAST(CURRENT_TIMESTAMP AS DATE))