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Old October 27th, 2004, 03:57 PM
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Default when to use is Null and =null and"null

if (iEmpID ==""){
 if dateFrom = "" then
    strUpdate = strUpdate + " and dtRateFrom is null"

  if resType="E" then
    strEmpID = cstr(iEmpID)
    strSubID = "null"
Please let me know what is the difference between is null and =null and "null" As shown above why I am using three different cases of null
in the above three codes. Please help me. I will appreciate your suggestions and comments. Thanks

Old October 27th, 2004, 08:05 PM
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  var n1,n2=null,n3=="null";

  n1 is declared but not initialised so it is equivallent to null.
n2 is assigned null.
n3 is string variable contains value "null". Its not eq to null.

    alert("n1 is null");
    alert("n2 is null");
    alert("n3 is \"null\");


Old October 28th, 2004, 07:39 AM
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Use is null when checking the status of a field in sql:

select * from table where field1 is null

Use = null when assigning

update table set field1 = null

"null" is a string value that says null.

Old October 29th, 2004, 01:47 AM
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Hi Shoakat,

Did you do a search on this here, you would find a handfull of such threads discussed on that NULL subject that should be useful to you.


- Vijay G
Strive for Perfection

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