CASE/IF with cast

Question

我一直有一個錯誤，我不明白爲什麼，我希望你能幫助我。我想提出以下表達式：

CAST((pwdLastSet0/864000000000.0 - 109207) AS DATETIME) AS 'PasswordLastSet',dateadd(d, 80, CAST((pwdLastSet0/864000000000.0 - 109207) as DATETIME)) AS 'expirationdate' 

因爲如果我的列值pwdlastset0爲null，則無法進行計算。

所以，我想兩個形狀：

case 
    when pwdlastset0 !=0 
    then 
CAST((pwdLastSet0/864000000000.0 - 109207) AS DATETIME) AS [Password Last Set],dateadd(d, 80, CAST((pwdLastSet0/864000000000.0 - 109207) as DATETIME)) AS 'futurdate' 
    else 
pwslastset0 = 'The password has never been set' 

和

If pwdlastset0 !=0 
then 
CAST((pwdLastSet0/864000000000.0 - 109207) AS DATETIME) AS [Password Last Set],dateadd(d, 80, CAST((pwdLastSet0/864000000000.0 - 109207) as DATETIME)) AS 'futurdate' 
else 
pwdlastset0 = 'The password has never been set' 

我想沒有 「AS」，也改變我的病情，我的意思是，如果= 0，則顯示「未還沒有設定'其他的教育。無論如何，我無法讓它工作，所以如果你們有任何想法我還沒有嘗試，非常感謝你！

Answer 1

pwdlastset0 !=0不檢查NULL。使用IS NULL表達：

case 
    when pwdlastset0 IS NOT NULL 
    then 
CAST((pwdLastSet0/864000000000.0 - 109207) AS DATETIME) AS [Password Last Set],dateadd(d, 80, CAST((pwdLastSet0/864000000000.0 - 109207) as DATETIME)) AS 'futurdate' 
    else 
pwslastset0 = 'The password has never been set' 

Answer 2

更改比較，以檢查是否pwdlastset0大於0如果不大於0，則返回密碼從未設置。

case 
    when pwdlastset0 > 0 
    then 
CAST((pwdLastSet0/864000000000.0 - 109207) AS DATETIME) AS [Password Last Set],dateadd(d, 80, CAST((pwdLastSet0/864000000000.0 - 109207) as DATETIME)) AS 'futurdate' 
    else 
pwslastset0 = 'The password has never been set'